"France has recorded national estimates of the number of problem drug users since the mid 1990s. The last estimate produced by the OFDT relates to 2011 data and follows on from earlier estimates in 1995, 1999 and 2006. The definition of problem drug use has, however, changed from one study to the next: in 1995, the inclusion criterion for this category was the use of opiates; in 1999, this criterion was extended to include cocaine. The definition proposed by the EMCDDA in 2004 was adopted for the 2006 and 2011 estimates: the concept of problem drug users includes users (between 15 and 64 years of age) of all drugs administered intravenously or regular users of opiates, cocaine or amphetamines. There is, however, a slight difference between the approach used in France and EMCDDA recommendations. In the studies conducted in 2006 and 2011, all patients who had consumed the aforementioned substances or administered drugs intravenously within 30 days prior to the study were considered to be problem drug users. The use of this inclusion criterion does not, however, indicate whether use has been ongoing for one year – a condition stated in the European protocol. The purpose of this criterion was probably to exclude “occasional” users. In practice, almost all recent users of these substances or of intravenous drugs seen in treatment and harm reduction centres are long-term users."

Source

l'Observatoire francais des drogues et des toxicomanies (OFDT), "2012 National Report (2011 data) to the EMCDDA by the Reitox National Focal Point: France: New Development, Trends and in-depth information on selected issues (Saint-Denis, France: OFDT, 2012), p. 60.
http://www.ofdt.fr/BDD/public…