@Anders_S @Tutanota @ecosia @Qwant @kagihq @StartpageSearch @duckduckgo for French searches yes, for others not so much. Some time ago it was possible to tell by using the report results button. However it seems the button is gone when it let you select individual results, they were from Qwant, if it forwarded you to Bing they were, well from Bing.

@hacks4pancakes German here, I was raised with the switcheroo and I think almost everyone does it here