PARIS, Oct 9 (Reuters) - French court ruled on Friday in favour of trade unions seeking to block the sale of a 29.9% stake in Suez to Veolia, unions told Reuters.

The works council of Suez filed last month a lawsuit aimed at suspending larger rival Veolia's bid for the group.

The council said the court had allowed to sue because the works council had not been consulted over the bid, as is required under French law.

(Reporting by Matthieu Protard and Geert De Clercq, editing by Louise Heavens)