No, it should be fine. Your luggage can normally be checked through. (And even if not, the EU is a customs union and so no customs checks would normally be made between the UK and France.) Because the UK is not in the Schengen area and France is, you will not need to clear exit immigration control in France since you will remain as an "international" passenger in transit. You might have to go through passport control on leaving the UK (sometimes you do, sometimes you don't, and it's difficult to predict) but of course that won't affect your transfer time when changing planes in France.