Does he actually think that the jihadists will walk around with a leg tag on? He must be crazy. If they are dangerous enough to tag then they should be deported or jailed. If they are French citizens, strip them of citizenship and give them the choice of jail or a country of their choosing.
Deported? Drown them in bacon grease.
Why tag them! So you know where they are when they start shooting or bombing your citizens? What an idiot.