Minute papillon, literally “Minute, butterfly”, means “slowly” or “hold your horses”. The expression dates back to the 20th century. However, its origin is not very clear.
It might be a reference to the butterflies that flit from flower to flower but never stop for a very long time.
But, according to another story, the expression would be related to a Parisian café popular with journalists. There was a waiter called Papillon. He used to answer “Minute, j’arrive” when too many people were calling him at the same time. And apparently, when customers – and the journalists who spread the story – wanted to tell him to take his time, they would say “Minute, Papillon”