The French parliament definitively adopted a set of contentious labour reforms on Thursday which sparked months of violent protests against a package seen as a threat to cherished workers' rights.

Prime Minister Manuel Valls used a constitutional tool to force the legislation through parliament three times, to avoid rebel Socialist backbenchers sinking it.

After a lengthy bicameral shuttle the reforms were considered adopted on Thursday afternoon after no lawmakers called a vote of no confidence in the government.

In a sign of the divisions among the Socialists, lawmakers from the ruling party were only two votes short of calling a vote of no confidence.

The Republicans opposition party said it would take the matter to the constitutional council, and the Left Front said it would do the same to denounce "a forceful passage which only strengthens a democratic crisis in our institutions".

Valls praised "a great step for the reform of our country: more rights for workers, more visibility for our small and medium enterprises and more jobs."

The proposed labour reforms are aimed at making the job market more flexible and reducing unemployment, stubbornly high at around 10 percent.

But critics see the measures, which would make it easier to hire and fire people, are too pro-business and would fail to bring down the jobless count.