Do you really think france will just abandon their tradition of a very liberal atheist society because of a few terror attacks? "Welp guys, it was a good run for the last few hundred years, but now its time to give sharia a try. Can't afford any more dead bodies!".
No. the only objective of terrorists is to bring terror. They do this so that they can divide the populace, and push un-radicalized muslims over the edge to make more terrorists. They want the non muslims to hate the muslims MORE by these actions (if it even was islamists, we dont know at this point). So your really just playing into the hands of the terrorists by spouting your islamophobias, and joining them on the hate train.
The correct solution is to treat this as a crime, like any other and punish those responsible. Don't go trampling on the rights of ALL muslims / citizens because of a few extremists. That is the objective of terrorist acts!!
But that's how the french would/should deal with it. Americans would deal with it by over-reacting, invading countries, and creating more terrorists in the middle east. See how well that worked for you guys? No worries, you'll get it at some point. You cant fight terrorism with more violence. It's a never ending cycle, and thats exactly what the islamists want!!!! perpetual instability.