Kidnapping a French wizard who happened to be a Veela seemed like a worse and worse idea the more he thought about it.  It wasn't that he thought Jean should be allowed to just wander around infecting people right and left with a disease that was trivial to him and deadly to them.  He just didn't fancy a stint in Azkaban for trying to make this right.  The Ministries of both France and Britain were unlikely to understand.  Government never did.