Visiting between two visas

I use six-month visas to spend time at my French home. Can I go to France for up to 90 days in the period between when my six-month visa expires and a new one starts? I am thinking of selling up and will need to access the house at other times.

In short, yes, periods under a visa are not counted as part of your 90/180 visa-waiver days, so this is possible.

However, visitors to France should normally not spend more than six months in total here in a given calendar year if they do not plan to move and become a tax resident.

If it is a one-off situation and you only exceed this by a small amount, it may not be picked up on by the authorities, but it is not advisable.