In 1931, Lacasse founded Galerie l'Equipe, an open platform to young artists seeking recognition. During 1931-1937, l'Equipe was active in Lacasse's studio located 11 Impasse Ronsin, the famous artists' alleyway in Montparnasse. An official gallery space on the Boulevard Montparnasse was rented during 1937-39. Amongst the artists exhibited at Galerie l'Equipe were Sonia and Robert Delaunay, Gleizes, Picabia, Vantongerloo, Lurçat and Picasso. During the l'Equipe period, Lacasse explored the possibilities of light, space and form, drawing on his experiences of working as a child in the stone quarries of Tournai, Belgium. During 1935-36, his ultimate search for light pushed him to experimenting with stains and spots of colour without subject or form, culminating in a series of small works, which are considered Tachist 'avant la lettre'.

The works of Lacasse are included in the following museums: Musée d'Art Moderne de la Ville de Paris; Musée National d'Art Moderne; Centre Pompidou, Paris; Musée des Beaux-Arts, Brussels; Musée de Tournai, Tournai; Musée des Arts Décoratifs, Paris; Tel Aviv Museum of Art, Tel Aviv; Eilat Museum, Eilat; Carnegie Institute, Pittsburgh; National Gallery of Victoria, Melbourne.