That has not prevented the Sarkozy camp - and even the President in person - throwing lumps of mud at Trierweiler. The presidential campaign has let it be known that the TV and magazine journalist is "cold", "not liked", "known as the Duchess" and that she "voted Sarkozy last time".
The President has himself suggested - wrongly - that Trierweiler is a "friend" of wealthy media barons. He also criticised her appearance with Hollande at a memorial service for the soldier victims of the Toulouse killer.
In an interview with the newspaper Liberation, Trierweiler, 47, said: "I don't understand his attitude. No one is attacking his wife. What reason has he got to let loose at me? It's not worthy of a President."
There has been some criticism of Bruni-Sarkozy, but mostly from within the President's own camp. "There are some people who think that she is too passive," said one official in Sarkozy's party, the Union pour un Mouvement Populaire.
In an interview with the magazine Le Nouvel Observateur last week, Bruni-Sarkozy said she was doing as much as her husband wanted. Compared to previous first ladies, such as the politically active but conservative Claude Pompidou, "I am Lady Gaga" she said - in other words media-savvy but a political novice. Bruni-Sarkozy also revealed that she liked occasionally to travel around Paris incognito wearing a wig. Independent