That is correct.
We are not allowed by France to request a licence swop until 6 months before our UK licence expires in the normal course of things.
This has been covered (very) extensively on other threads here. The supreme info is on Kim’s Facebook page and she has kindly popped in here a few times to clarify things. There are other threads in this long saga but this one will give you a flavour:
If you want a French licence earlier you either have to get it mangled to an unreadable form in some sort of mishap, lose it or commit an infraction in France requiring you to swop so they can take points off.
Those of us who.don’t have an address in UK, so were always told we were committing an offence if we did not keep our licence address up to date, are caught in am impasse as we have to keep our UK licence but can’t update it.
A solution against zealous but unknowledgeable UK traffic cops could be to apply to ANTS for an International Driving Licence (no fee) off tbe back of your being resident and having a UK licence - that appeared in a thread here earlier this year and I am thinking of doing it.