After some troubles with lists about six decades ago, France has decided to keeps its various lists separate, and is wary about attempts to mesh them.

Voter rolls are only used for jury and poll purposes, and are set up by the municipalities ; Tax rolls don't care about nationality, and are set up by the State. Also means that you can vote even though you are cheating the tax man, also,tax rolls probably don't know everybody ; married couples count as one for the tax administration, etc... Finally, some people might chose to vote in their village in the province but pay tax in Paris... (e.g. All politicians vote in their fief in some small provincial village, but live in Paris most of the time)

Un roi sans divertissement est un homme plein de misères