There he entered the Académie Julian,[2] where he studied under Tony Robert-Fleury and Jules Joseph Lefebvre.
During his years (1887–1890) at the Académie Julian, his colleagues included Maurice Denis and Paul Ranson.
On his return to Paris, he visited Montmartre and became friends with Alfons Mucha and Léon Deschamps, editor of La Plume.
He also met Hugues Delorme and Jules Roques at Le Courrier français, giving rise to a fruitful collaboration with (among others) Willette to provide illustrations for it.
At the turn of the century, Widhopff was in the service of the Vollard gallery, the gallery belonging to Ambroise Vollard, one of the most important dealers in French contemporary art in the twentieth century.