It was in his spare time that he opened up to the artistic avant-gardes of his day. In the 1920s, he co-founded the Ziniars, a group that, as its name suggests (derived from the flower zinnia), was characterized by a desire for original, lively expression. The Ziniars played a key role in the creation of the Salon du Sud-Est in 1925, an event that promoted modern art in the region and fostered artistic exchanges between Lyon and Paris.
Didier's interest in the avant-garde was strengthened by his discovery of the works of Fernand Léger and André Derain, two major figures in the Fauvist and Cubist movements, whose works had a profound influence on him. He also participated in Lyon-based art magazines such as Manomètre (1922-1928) and Promenoir, publications that highlighted modern trends and innovative painting practices, while providing fertile ground for artists like Didier to experiment and publicize their creations.
His active participation in these avant-garde circles and his involvement in Lyon's artistic life gradually established him as an important player on the local scene. However, his work, marked by modernity and influenced by abstraction and the search for new forms, remains a precious testimony to the creative diversity and artistic dynamics that ran through the first half of the 20th century.