That depends on myriad factors, including what my business is, what my market is, where the trained labour force is situated, what the local infrastructure is like and lets not forget
the quality of any graduate recruits I might need.
France has a considerably higher productivity per hour worked than the UK. More than 25% higher, in fact:
So that's something I might bear in mind when choosing where to site my business.
And to point out the obvious: France has about the same GDP for about the same population as the UK (
source), so businesses are obviously not all flocking from France to the UK in spite of corporation tax being twice as high there.