This study examines occupational exposure to formaldehyde among all workers aged 20 to 74 in France in 2015. Exposure to this known human carcinogen (classified as Group 1 by the IARC) is assessed using the Matgéné program’s occupation-exposure matrix. Population data from the 2015 census (2013–2017) were cross-referenced with the matrix to estimate the prevalence of exposure by economic sector, occupation, worker status, and gender. The matrix was also cross-referenced with the 1982, 1990, 1999, and 2007 censuses to describe changes in exposure prevalence over this period. Exposure to formaldehyde has declined sharply over the past 30 years, falling from 822,000 potentially exposed workers in 1982 (36.6‰) to 90,000 workers in 2015 (3.5‰). Among these exposed workers, 56% are employees and 44% are self-employed. Among employees, the three sectors with the highest number of workers potentially exposed to formaldehyde are agriculture (19.1% of those exposed), specialized construction work (16.3%), and human health activities (9.6%). Among the self-employed, the three sectors with the highest representation among exposed workers are agriculture (50.4%), specialized construction (23.7%), and other personal services (15.7%). The occupations with the highest number of exposed workers are also detailed. This article is the first to describe occupational exposure to formaldehyde in France for all workers. The results presented help identify the sectors and occupations still exposed in 2015 despite various regulations limiting its use, and contribute to the development of prevention policies to target efforts toward the occupational groups most at risk.