France certainly has a social problem, with immigrant-descended populations often living precariously in crime-ridden banlieues, relatively isolated from the “indigenous” French people. These are great conditions to breed extremism.
But I’m not sure you could go so far as to say that there’s really a terrorism problem. Of course any terrorist attack will be a huge thing in the news, but looking at the bigger picture, it still happens rather rarely and France is overall a pretty safe country.