Screed floor: Primer before tiling?

Hello everyone, what is your experience: we want to lay tiles on the well-executed screed floor. Is a primer needed beforehand? The screed floor apparently absorbs moisture quite tightly, which is why I was told that a primer coat is necessary... What do you say?

The datasheets of the tile adhesives typically provide quite precise information about substrate preparation. I would take a look at those and follow them.

The tiler applied primer [Haftgrund] at our place.

Of course, it should be done, you don't need to save those few cents per m²...