The anti-terror laws, which affect all French nationals including individuals who didn’t grow up in French territories, were enacted by President François Hollande on Friday and came into effect on Saturday.
The tightening of the legislation will see “criminal association with a terrorist group” punishable with up to 10 years in jail and a fine of 225,000 euros.
The bill also extends the provisions of the Temporary Act of 23 January 2006, to include monitoring telephone and Internet data.
It comes after French Jihadist Mohamed Merah killed seven people in a shooting spree in the south of France in March.
Investigators believe that Merah, who claimed to have links to Al-Qaeda, received training along the border between Pakistan and Afghanistan.