Cancer is the leading cause of death in France, although the mortality rate among cancer patients has declined and cures are becoming increasingly common. With approximately 148,000 deaths in 2012 and more than twice as many new cancer cases (approximately 355,000), it represents a public health priority that is growing alongside life expectancy. The fight against cancer in France has been a government priority since 2003, having been the focus of two successive “Cancer Plans.” A third Cancer Plan for the 2014–19 period focuses on the issue of inequalities. The establishment of Regional Health Agencies (ARS) has led to a significant decentralization of public decision-making in the health sector in France and has increased the importance of having data available at this geographical level.