Life on benefits can be quite good for those who know how to play the system, otherwise there wouldn't be so many who are happier doing so than getting a job and working for a living. I personally know people who live quite nicely on benefits...far better than I do in fact, and I worked right up to retirement age.
Some of those unfortunates now in France waiting for the opportunity to get here will probably work illegally, but others among them will claim asylum and be looked after by the state.