In which country did the Merz conservatives achieve a local election win amidst significant gains by the far-right AFD party?

The Merz conservatives, referring to the Christian Democratic Union (CDU) under the leadership of Friedrich Merz, achieved a noteworthy local election win in Germany. This victory occurs in the context of broader political dynamics in the country, particularly with the notable rise of the far-right Alternative for Germany (AFD) party, which has been attracting attention and voter support in various regions. This local election success for the Merz conservatives highlights the ongoing struggle and shifts within Germany's political landscape, where traditional parties are navigating competition from populist and far-right entities like the AFD.

The other countries listed—France, Italy, and Spain—have their own unique political situations, but they do not feature the Merz conservatives or the specific dynamics involving the AFD party, which is distinctly a German phenomenon. Thus, Germany is the only correct context for this particular question about the Merz conservatives' electoral outcome amidst the AFD's influence.