A new offence of creating an "individual terrorist enterprise", designed to counter the threat of "lone wolves", would also be established.
Government officials say that two or three young Muslims leave France every day to join Islamist groups abroad.
There are fears they will eventually pose a threat to France itself.
A French citizen arrested for the killing of four people at the Brussels Jewish Museum in May, Mehdi Nemmouche, had returned from Syria, after being radicalised in prison.
Another French-born jihadist, Mohamed Merah, killed seven people in Toulouse in 2012 before being shot by police. His victims were three paratroopers as well as three children and a teacher at a Jewish school.
EU counter-terrorism coordinator Gille de Kerchove announced on Tuesday that interior ministers from nine countries had adopted an action plan to identify people travelling to Syria and stop them falling into terrorism on their return.
The countries that signed up to the plan are Belgium, France, Germany, the UK, Spain, Italy, Denmark, Sweden and the Netherlands » | Wednesday, June 09, 2014
