Valadon was Utrillo's mother. This is a kind of unbelievable fact of art history (and of course for years, while Utrillo was being celebrated as a great Post-Impressionist painter, his mother was ignored). And their work was so different! Although they both painted French suburban life, they observed it from opposite directions. Here is Valadon's 1921 portrait of her son, it's in Paris at the 

musée Montmartre