Pupils walk in the playground at Flaeming primary school during a nationwide one-day warning strike by public sector educational union (GEW) in Berlin March 3, 2015.Trade unions are demanding a 5.5 percent pay rise for some three million civil servants. Unions argue that the public sector has failed to keep pace with private sector wage rises. Employers have rejected their demand as lacking "any sense of reality". The sign reads: "We are on strike". REUTERS/Fabrizio Bensch (GERMANY - Tags: EDUCATION BUSINESS EMPLOYMENT CIVIL UNREST TPX IMAGES OF THE DAY)