@FediTips @jssfr
That doesn’t seem correct.
The 1st vote is for the district representative - which is first-past-the-post and thus voting for a party that has a realistic chance of getting to the majority in the district is sensible - especially if it’s about preventing another party from gaining the seat. In some districts (such as mine) parties that have a small share of the national vote can still have a strong local footprint and there the 1st vote is a good way to support them - but that’s not true for most districts.

The 2nd vote is proportional, so there small parties will have as much a chance as those with a large vote share. Nonetheless the party still needs to cross the 5% threshold, so voting for a party polling at below 3% is not a great strategy if one would want to prevent the AfD from gaining seats.