His work moved from the aggressive imagery of the post-war years toward architectural theories. He spent nearly twenty years developing New Babylon, a series of models and drawings for a nomadic global city. In works like 'La ville noyée', he uses line and wash to suggest structures that exist between solid and liquid states. His technique involves thin layers of oil or watercolour that create a sense of space without traditional perspective.

Collectors value Constant for his ability to bridge the gap between abstract expression and social commentary. His prints offer a sense of movement and structure that fits well in minimalist or mid-century modern interiors. The work feels contemporary because it addresses themes of urban living and human freedom through a clear, graphic style.