Sonia’s later years were characterised by both large format paintings and smaller formats in series, such as Avec Moi-même 1970, which was produced in collaboration with the publisher Jacques Damase. She illustrated a number of books of poetry, returning to her early interest in the relationship between abstract art and literature. She continued to design tapestries, which were manufactured by leading workshops such as Gobelin and Pinton.
Throughout her later work Sonia re-interpreted previously used shapes, transforming them into a new abstract language, as shown in her painting Syncopated Rhythm, known as the Black Snake 1967.
By this point, Sonia had become recognised as an essential reference for a new generation of abstract artists. She died in Paris in 1979 at the age of 94.