Letting hundreds of thousands of military age men into you country, with no way of verifying who they are is not a safe thing to do. I wasn't shocked when I heard about the attacks last month, especially with all the other violence that recent immigrant men in Europe have been doing.
Have you realised how only the countries in the west that have attacked ISIS have been victims of terrorist attacks?
Just a few weeks ago the fanatic in london attacked people in revenge for Syria bombings.
In America a muslim couple killed some people because of us led air strikes.
In france they should have expected an attack.