French lawmakers have opened the way to passage of a bill that would allow spying on communications overseas, hoping to legalize a practice that intelligence services already use to keep tabs on extremists who have joined jihadis in Syria and Iraq.

The bill was adopted in a first reading on Thursday with few lawmakers present in a sign of smooth sailing for the measure that critics say risks compromising fundamental rights.

With the prime minister's authorization, it would notably allow the interception of any international communication "sent or received" in France by both French citizens and foreigners.

Amnesty International said the "reach of this law is so large it gives ... intelligence agencies a blank check." The bill now goes to the Senate for debate.