The figures are based on the findings of a government agency poll and could be an underestimate, according to Insee statisticians, since some respondents may have distrusted the pollsters.
An estimated 3.1 billion euros-worth of drugs are consumed in France each year, according to the findings, but 400 million euros represent imports and so must be subtracted and credited to the GDP of the exporting countries, leaving a balance of 2.7 billion euros.
France's trade in cannabis is worth a billion euros and that in cocaine 800 million euros, according to the estimates.
The statistics are the first ever produced in France on the contribution of drug trafficking to the economy.
Refusal to count prostitution
They arise from a request from the EU's Eurostat institute to include the proceeds of the drug trade and prostitution in GDP figures, because they are legal in some countries, such as the Netherlands, and so already included in those countries' official statistics.
The change has been responsible for a considerable rise in the official GDP of some countries, espacially Italy and Spain.
Eurostat defined the drug trade and prostitution as commercial transactions that have been freely entered into.
President Emmanuel Macron's government has ended prison terms for cannabis use, on the grounds that they were ineffective, but has not legalised consumption or sale of the drug.
Insee has refused to include prostitution in its figures, arguing that "street prostitution is notoriously practiced by people who are usually undocumented, often minors and controlled by secret networks that have brought them to France".
A 33-year-old man was shot dead on Tuesday night in Menton, a town on the Italian border, in what is believed to be a drug-related killing.
Another man, who went to a hospital with injuries to his legs, has been detained as his role in the shooting is clarified.