With all the dross going on about Brexit, have I missed something.
I was under the impression that you only had to exchange your license for a French one if it was expiring , you got points, or you lost it.
Having just read the Govt advice on living in France. It now appears that if you are French resident your UK license will only be valid until 31/12/21, and you have to exchange by that date.
Sorry your understanding that you do or you don’t need to change. I read not long ago. The french prime minister stated that no uk license holders have no reason to change a license the french will recognise an english driving license then again things may have changed.