It's something of a truism in polling that you can find a majority in favour of holding a referendum on just about any subject you want. So in this case, C"News" commissioning a poll on this is just a partisan attempt to push the public discourse in a direction that is closer its own fantastical obsessions.
As it is France already has basically the lowest level of immigration of every Western European country, and net migration that is barely positive, so it's not like they have especially much to complain about on the subject.
To be fair, perhaps asking more directly "Do you think that immigration to France should be more heavily restricted?" or something along those lines would make for a better poll but given trends in France I am fairly convinced that the result of the poll (or a hypothetical referendum) would be "yes".
Also, is France really a place that isn't attracting immigrants at all? France isn't exactly the wealthiest Western European economy or the one with the best job market but the situation there is still pretty good and most immigrants, or at least the ones that people "worry about" (ie refugees from Africa and the Middle East); in many cases speak French as their own native language or as a 2nd language.
