"Cannabis is still by far the most widely used illicit substance, both among teenagers and the adult population, with 17 million people having already tried it (i.e. 41% of 15 to 64 year-olds). The overall proportion of recent users (in the last month) is 6.6%, and regular use (at least 10 times per month) concerns nearly 1.5 million people in France.
"Among last year users aged 18 to 64 years, according to the 2014 INPES Health Barometer Survey, the proportion of those at high risk of problem cannabis use is 21%, i.e. 2.2% of the French population aged 18 to 64 years. Cannabis is also the most frequently reported substance mentioned as the principal reason for entering drug treatment (CSAPA). As far as synthetic cannabinoids are concerned, 1.7% of adults aged 18 to 64 state that they have already used such substances. Their use levels are similar to heroin or amphetamines.
"Cannabis use has been on the rise since the beginning of the 2010s, regardless of age group and frequency of use: this rise is part of a context of a marked increase in cannabis supply in France, particularly home cultivation and local production of herbal cannabis, while the cannabis resin market is still very dynamic.
"The use of cocaine, the second most frequently used illicit substance, is far below that of cannabis and concerns approximately one tenth the number of people. However, the proportion of lifetime cocaine users aged 18 to 64 has increased four-fold in two decades (from 1.2% in 1995 to 5.6% in 2014). This statistic includes those who have used cocaine at least once in their life (lifetime users) or at least once in the last year. This variation indicates the wider diffusion of a substance once limited to well-off categories, and affecting all social groups in recent years. The levels of lifetime use for synthetic drugs such as MDMA/ecstasy and amphetamines are 4.3% and 2.3%, respectively. The proportion of current MDMA/ecstasy users increased significantly between 2010 and 2014 (from 0.3% to 0.9%), thus reaching a peak since the last decade.
"The prevalence of lifetime use of heroin is 1.5% in the entire 18 to 64 year-old population and current use seems very rare (0.2% of those surveyed)."

Source

l'Observatoire francais des drogues et des toxicomanies (OFDT), "2015 National Report (2014 data) to the EMCDDA by the Reitox National Focal Point: France" (Saint-Denis, France: OFDT, 2016), p. 31.
http://en.ofdt.fr/BDD/publica…