Where in Europe is this? Europe isn't a monolith, after all.
Here in the Netherlands we (currently) still have the "salderingsregeling" which is used to reimburse people for the solar they feed back into the grid, though that will eventually go away.

Paying people for solar on the roof is a bit tricky in general, and probably not sustainable long term:

• The money to maintain the grid has to come from somewhere, and if a lot of people have a bill of zero euros or a negative amount, that system kind of breaks down.
• The grid has a maximum capacity (especially in residential neighbourhoods) so you cannot pump an infinite amount of power back into the grid. If many houses in a neighbourhood have solar the grid simply cannot cope.