> ... although I believe you need a positive PCR test for that, an antibody test is not sufficient.
Most countries in the EU just relaxed the requirements to travel before the summer vacations. You don't need a PCR test anymore to travel: just an antibody test (at least for Spain / France / Belgium but I take it many others are doing the same). And there's no requirement to be vaccinated.
They also raised the age at which you need a test from 6 to 12 years old.
Source: always living/traveling across France/Belgium/Spain.
Fun fact: when you travel by car in the EU they typically do not bother to check. You can cross several countries and they're not verifying anything. Another fun thing: test is supposed to be less than 72 hours old, so if you're traveling over more than 3 days, you need to get re-tested during your trip.