After studying engraving for six years at the Cami workshops of the Beaux-Arts de Paris, Claude de Soria took painting classes from André Lhote and Fernand Léger, as well as sculpture lessons from Ossip Zadkine. Her first works were made out of terracotta and shown at the galerie Claude Bernard in Paris in 1965. In the late 1960s, she created her first abstract sculptures, the series Murs [Walls], by beating slabs of clay with pieces of wood. From then on, her research turned to exploring the formal potential of various materials. The inspiration for this hit her when she came across an abandoned half-empty bag of cement. She poured the bluish-grey cement onto a sheet of mirror and was surprised to discover the intense change it had gone through when she unmoulded it, with undulations and air bubbles rippling across its underside. She was drawn to this transformation of matter and decided to work on this “underside”, which accumulates all the mishaps that are not supposed to be seen.

At first, she created concrete pours on Rhodoid (plastic material; Plaques [Slabs, 1974–1975], before making prints on paper, like precious disks, their mineral composition similar to planetary symbols. Her Boules en deux parties [Two-Part Spheres, 1976–1978] were the result of filling plastic half-spheres and assembling them into pairs. Later on, her explorations of verticality led her to pour cement into tubes, resulting in the series Lames (Blades) and Contre-lames [Counter-Blades, 1984–1985]. She then reverted to circular shapes with her Ouvertures [Openings, 1987], which consisted of perforated disks with jagged edges. Her prolific production of raised or three-dimensional pieces highlights her constant search for randomly achieved formal and chromatic surface effects, which she strived to reproduce by encouraging natural processes and letting matter fully express itself. C. de Soria is one of the few artists to have used cement during the 1970s, a time when it was considered a lowly material. In doing so, she contributed to its revival.