If you drop it now, no university will ever even know you took French in the first place since you didn't sit exams for it. The only disadvantage would be if you tried to apply to UCL which to my knowledge asks for a pass in a modern foreign language - although this was on the old GCSE system so I'm not sure if it applies now and I'm also not sure if this goes for all subjects.
Other than that, you should be fine.