Belgians in Africa are unsurpassed, though :-(
I rank Spain crimes a bit lower because South America colonization is far in the past, in an era where certain crimes was not considered much crimes from the point of view of most populations, otherwise they would be at the top position, perhaps counting also they religious crimes against also their own citizens.
Anyway any power have a blood trail, that's just a rank for the most "recent" ones...
But, no, Vietnamese people can not get French citizenship on special conditions and never could. But they was killed & tortured on the grounds of owning too thick and too long stick, and French soldiers sent postcards with such photos to home! It was not 18 or 19 century, as in Americas, but 1910-1920!
On the other hand, British not only build roads and railroads in India (Myanmar railroads built by British colonial administration are still in use, including some gorgeous and highest mountain bridges), but cut weavers' hands in India, too.
Ok, I can not rate them all. It is just bad.
France was one of the less oppressive colonizers in Africa, but still left a significant trail of blood and suffering behind so while with Mali there was an agreement because western-created (yes, you read correctly) "islamic" militias are worse for Malian than French colonial legacy, though when Russia step-in it was and perhaps still is considered better: they do not really have means to colonize, they can just make agreements less unfair perhaps than western countries.
And that's happen almost everywhere, China is far less welcomed because various populations already experience China BRI policies and so the news they are not much friendly than the west is already spread. You do not need more resources than just history. The worst western colonizer were, from the more bloody and oppressive:
- Dutch & Belgian & British
- Germans & Italians & Spaniards
- Frenches & Portuguese
Chinese are "new" outside China, so are Russians and Russians are still seen a bit as Soviet witch to gain influences was far lighter than anyone else outside their borders.