More of them stay in France than come to the UK, and that was the case long before Brexit too. Why should we not do our bit just because of geography?
You and I are lucky enough to have been born in a rich, developed country with endless opportunity. Others have completely different circumstances through no fault of their own. The lives of an overwhelming majority of the population aren't impacted at all by immigrants, mine certainly never has been. I doubt yours has either although I might be incorrect.
We have one of the biggest economies in the world, it's not unreasonable in the 21st century that we should be expected to take a little bit extra strain to help people less fortunate than ourselves.