"A sub-IR IMC privilege would work well in France.
Put a limit of FL110 on it, that keeps it below the major Class D base but would allow transit of the Class D airport zones"
Precisely why I advocate referring to 'permitted' airspace for individual states to decide, rather than an universal one-size-fits-all decision imposed upon them!
We had this for military low level flying - the rules were different for Belgium, Holland and Germany. I once had a low level flypast to do in Belgium, but we had to approach from the east close to 'Dreilandenpunkt'. So 3 different sets of rules to adhere to in the space of 5 minutes! Not hard, just took careful preparation.