Prince Albert II of Monaco arrives with his daughter Princess Gabriella to attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco holds his son Prince Jacques during the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (R), his wife Princess Charlene (L) and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their daughter Princess Gabriella arrive at the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco holds his son Prince Jacques during the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (R), his wife Princess Charlene (L) and their twins Prince Jacques (2ndL) and Princess Gabriella (2ndR) arrive to attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

(L-R) Camille Gottlied, Louis Ducruet, Princess Charlene, Princess Gabriella and Prince Albert II of Monaco arrive for the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Princess Charlene of Monaco (C), Prince Albert II (R) and Louis Ducruet (L) give presents to Monaco's children during the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco and his wife Princess Charlene of Monaco give presents to Monaco's children during the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (C), Princess Charlene (L), their son Prince Jacques (2ndL), Camille Gottlied (2dnR) and Louis Ducruet (R) attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco, his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (C), Princess Charlene (L), their son Prince Jacques (2ndL), Camille Gottlied (2dnR) and Louis Ducruet (R) attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (C), Princess Charlene (L), their son Prince Jacques (2ndL), Camille Gottlied (2dnR) and Louis Ducruet (R) attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (R), his wife Princess Charlene (L) and their twins Prince Jacques (2ndL) and Princess Gabriella (2ndR) arrive to attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (R), his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (R), his wife Princess Charlene and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco (L), his wife Princess Charlene (R) and their son Prince Jacques attend the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 14, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco attends the IAAF Athletics Awards ceremony in Monaco, December 2, 2016. REUTERS/Eric Gaillard 

Prince Albert II of Monaco attends the IAAF Athletics Awards ceremony in Monaco, December 2, 2016. REUTERS/Eric Gaillard 

Tegla Loroupe of Kenya receives the IAAF President's Award from Prince Albert II of Monaco in Monaco, December 2, 2016. REUTERS/Eric Gaillard 

Tegla Loroupe of Kenya receives the Presidents Award from Prince Albert II of Monaco as IAAF's President Sebastian Coe looks on, in Monaco, December 2, 2016. REUTERS/Eric Gaillard 

Almaz Ayana (L) of Ethiopia is congratulated by Prince Albert II of Monaco after receiving the female World Athlete of the Year Award 2016 in Monaco December 2, 2016. REUTERS/Eric Gaillard 

Almaz Ayana (L) of Ethiopia is congratulated by Prince Albert II of Monaco after receiving the female World Athlete of the Year Award 2016 in Monaco December 2, 2016. REUTERS/Eric Gaillard 

Usain Bolt of Jamaica (R) is congratulated by Prince Albert II of Monaco after receiving the Male World Athlete of the Year Award 2016 in Monaco December 2, 2016. REUTERS/Eric Gaillard 

Usain Bolt of Jamaica (2nd R) and lmaz Ayana of Ethiopia (2nd L) pose with their awards and Prince Albert II of Monaco (L) and IAAF's President Sebastian Coe, after being elected male and female World Athlete of the Year 2016 in Monaco, December 2, 2016. REUTERS/Eric Gaillard 

Prince Albert II and Princess Charlene of Monaco pose for a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II and Princess Charlene of Monaco pose for a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II and Princess Charlene of Monaco pose for a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II (L) and Princess Charlene of Monaco leave after a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II (L) and Princess Charlene (C) of Monaco leave after a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert and Princess Charlene of Monaco pose for a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II (L) and Princess Charlene (C) of Monaco leave after a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool 

Prince Albert II (L) and Princess Charlene (C) of Monaco pose for a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool 

Prince Albert II (L) and Princess Charlene (2ndL) of Monaco pose for a family picture with refugees after a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool 

Prince Albert II (C) and Princess Charlene (2ndR) of Monaco attend a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II (C) and Princess Charlene (R) of Monaco attend a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II (C) and Princess Charlene (2ndR) of Monaco attend a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II (L) and Princess Charlene of Monaco attend a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Prince Albert II (C) and Princess Charlene (C,R) of Monaco attend a gift-giving event to Monaco's resident at the headquarters of the Monaco Red Cross in Monaco, ahead of Monaco National Day November 17, 2016. REUTERS/Valery Hache/Pool

Russian President Vladimir Putin (R) meets with Prince Albert II of Monaco at the Kremlin in Moscow, Russia, October 6, 2016. REUTERS/Yuri Kadobnov/Pool

Russian President Vladimir Putin (R) greets members of the delegation from Monaco during a meeting with Prince Albert II of Monaco at the Kremlin in Moscow, Russia, October 6, 2016. REUTERS/Yuri Kadobnov/Pool

Russian President Vladimir Putin meets with Prince Albert II of Monaco at the Kremlin in Moscow, Russia, October 6, 2016. REUTERS/Yuri Kadobnov/Pool

Russian President Vladimir Putin (R) meets with Prince Albert II of Monaco at the Kremlin in Moscow, Russia, October 6, 2016. REUTERS/Yuri Kadobnov/Pool

Russian President Vladimir Putin (R) greets members of the Monaco delegation during a meeting with Prince Albert II of Monaco at the Kremlin in Moscow, Russia, October 6, 2016. REUTERS/Yuri Kadobnov/Pool

Russian President Vladimir Putin meets with Prince Albert II of Monaco at the Kremlin in Moscow, Russia, October 6, 2016. REUTERS/Yuri Kadobnov/Pool

Formula One - Monaco Grand Prix - Monaco - 29/5/16. Mercedes F1 driver Lewis Hamilton celebrates after winning next to Prince Albert II of Monaco (R) and Princess Charlene. REUTERS/Eric Gaillard TPX IMAGES OF THE DAY

Princess Charlene and her husband Prince Albert II of Monaco arrives to meet Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi 

Prince Albert II of Monaco and his wife Princess Charlene waves as they leave after a private audience with Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi 

Prince Albert II of Monaco (2nd L) and his wife Princess Charlene (C) are welcomed by archbishop Georg Ganswein (L) as they arrive to meet Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi 

Prince Albert II of Monaco (C) and his wife Princess Charlene greets Vatican gentlemen as they arrive to meet Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi 

Prince Albert II of Monaco (C) is welcomed by archbishop Georg Ganswein (L) as he arrives to meet Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi 

Prince Albert II of Monaco (C) and his wife Princess Charlene are welcomed by archbishop Georg Ganswein as they arrive to meet Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi 

Prince Albert II of Monaco (L) shakes hands with archbishop Georg Ganswein as he arrives to meet Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi 

Prince Albert II of Monaco (L) shakes hands with archbishop Georg Ganswein as he arrives to meet Pope Francis at the Vatican, January 18, 2016. REUTERS/Max Rossi