Yellow vests are hung outside windows of an apartment building in support of the "yellow vests" movement in Marseille, France, December 7, 2018. REUTERS/Jean-Paul Pelissier 

Youths and high school students attend a demonstration to protest against the French government's reform plan, in Paris, France, December 7, 2018. REUTERS/Benoit Tessier TPX IMAGES OF THE DAY 

Pedestrians walk past wood panels protecting the "Cafe de la Paix" on the eve of a "yellow vests" protest in Paris, France, December 7, 2018. REUTERS/Charles Platiau 

Protesters hold a French flag as they occupy a roundabout as part of the "yellow vest" movement in Nice, France, December 7, 2018. REUTERS/Eric Gaillard 

Youths and high school students attend a demonstration to protest against the French government's reform plan, in Paris, France, December 7, 2018. The slogan reads "Another school = another society". REUTERS/Benoit Tessier 

Workers protect a shop window with wood panels on the Champs-Elysees Avenue near the Arc de Triomphe on the eve of a "yellow vests" protest in Paris, France, December 7, 2018. REUTERS/Philippe Wojazer 

A burning car is seen in the street as youths and high-school students clash with police during a demonstration against the French government's reform plan in Marseille, France, December 6, 2018. REUTERS/Jean-Paul Pelissier TPX IMAGES OF THE DAY 

French police apprehend a youth during clashes with youths and students who protest the French government's reform plan in Lille, France, December 6, 2018. REUTERS/Pascal Rossignol 

A vandalized car is seen in the street as youths and high-school students clash with police during a demonstration against the French government's reform plan in Marseille, France, December 6, 2018. REUTERS/Jean-Paul Pelissier 

French police stand ready during clashes with youths and students at a demonstration against the French government's reform plan in Marseille, France, December 6, 2018. REUTERS/Jean-Paul Pelissier 

A French flag and a yellow vest, the symbol of a French drivers' protest against higher diesel fuel prices, are seen at a roundabout in Roppenheim, France, December 6, 2018. REUTERS/Vincent Kessler 

French riot police face off with youth and high school students during a protest against the French government's reform plan, in Bordeaux, France, December 6, 2018. REUTERS/Regis Duvignau 

A French riot policeman walks past a burning car as youth and high school students protest against the French government's reform plan, in Nantes, France, December 6, 2018. REUTERS/Stephane Mahe 

Youths and high-school students attend a demonstration against the French government's reform plan in Marseille, France, December 6, 2018. The slogan reads "Angry high school students". REUTERS/Jean-Paul Pelissier 

Students attend a meeting at the Paris 3 New Sorbonne University campus as part of a protest to change the university system, in Paris, France, December 6, 2018. REUTERS/Charles Platiau 

High school students block the entrance of the Lycee Henri IV secondary school to protest against the French government's reform plan, in Paris, France, December 6, 2018. REUTERS/Gonzalo Fuentes 

Protesters wearing yellow vests, the symbol of a French drivers' protest against higher diesel fuel prices, occupy a roundabout in Cissac-Medoc, France, December 5, 2018. The slogan reads "Urgent, purchase power, dignity for all". REUTERS/Regis Duvignau TPX IMAGES OF THE DAY 

French ambulance drivers hold blue, white and red smoke bombs during a demonstration at the Place de la Concorde in Paris, France, December 3, 2018. REUTERS/Gonzalo Fuentes TPX IMAGES OF THE DAY 

French police apprehend a youth during clashes with students at a demonstration against the French government's reform plan in Marseille, France, December 6, 2018. REUTERS/Jean-Paul Pelissier 

French riot police stand near a burning car as youths and high school students protest against the French government's reform plan, in Nantes, France, December 6, 2018. REUTERS/Stephane Mahe 

A car that was vandalized by students is seen on a street near a technical school in Nantes, France, December 4, 2018. REUTERS/Stephane Mahe 

A protester wearing a yellow vest, the symbol of a French drivers' protest against higher diesel fuel prices, holds a flag near burning debris at the approach to the A2 Paris-Brussels Motorway, in Fontaine-Notre-Dame, France, December 4, 2018. REUTERS/Pascal Rossignol TPX IMAGES OF THE DAY 

Protesters wearing yellow vests, the symbol of a French drivers' protest against higher diesel fuel prices, occupy a roundabout in Sainte-Eulalie near Bordeaux, France, December 5, 2018. The slogan reads "Macron Get Out". REUTERS/Regis Duvignau 

Christophe Chalencon (L), one spokesman of the "yellow vest" movement, and Jamel Tobal, wearing yellow vests, watch French Prime Minister Edouard Philippe's speech at the French National Assembly, on a television screen at a bar in Paris, France, December 5, 2018. REUTERS/Philippe Wojazer 

Graffiti is seen on a vandalized wall at the Arc de Triomphe the day after clashes with protesters wearing yellow vests, a symbol of a French drivers' protest against higher diesel taxes, in Paris, France, December 2, 2018. REUTERS/Stephane Mahe TPX IMAGES OF THE DAY