French oil sector workers of the CGT trade union will join a national strike at refineries and other installations from May 17 to May 20 against a planned government reform of French labour law, a CGT union official told Reuters on Friday. The union will also propose to shutdown production at refineries and other oil sector sites during a May 20 meeting, Thierry Defresne, CGT union official at Total, said after a general assembly meeting of the trade union. "What we have decided this morning is to launch a strike on all refineries in France from May 17 in the morning until midday on May 20," Defresne said, adding that the strike will affect Exxon Mobil and Esso facilities.