Page "French name" Paragraph 9

When speaking of someone, Monsieur / Madame given name family name, by far the most polite form of address, is generally reserved for the most solemn occasions.

Monsieur / Madame family name or given name family name is polite and used in normal formal occasions, as well as in the formal quality press ( Le Monde, Le Monde Diplomatique, for example ).

By contrast, in colloquial usage the family names of personalities are used alone.

Formally, a married or widowed woman can be called by the given name of her husband ( Madame ( given name of husband ) family name or Madame veuve ( given name of husband ) family name ); this is now slightly out of fashion.