Plans hatched on the Internet to hold France's biggest impromptu drinks party in Paris later this month drew a formal warning on Thursday from the police who said the event could prove dangerous.
More than 13,000 people have already confirmed online that they will be turning up under the Eiffel Tower on May 23 for the "giant drinks party", or "aperitif" in French, and organisers hope to draw in more than 50,000.
Propelled by Facebook, a series of such gatherings have been gaining momentum over recent months, with thousands of people turning up for drinks in usually quiet cities like Rennes, Brest and Clermont-Ferrand.
"We are aware of the festive and friendly motivation of the participants, but there are serious risks associated with crowd management involving several thousand people," the Paris police said in a statement.
"Such a gathering cannot be organised without first examining and implementing adequate measures to protect the participants as well as public property," it added.
Police in the western city of Nantes also issued a warning to organisers of a similar event planned on May 12, which 12,000 people have signed up to.
Police said that in the last "giant aperitif" there in November, 38 people were hospitalised, about 50 were found unconscious from drinking and several fell into the Loire river and had to be rescued.
That event "caused incidents that endangered people's safety and damage to property for which the city of Nantes demanded financial compensation from the organiser," a police statement said.
The Paris police also noted that 14 people were taken to hospital during a giant drinks party in Rennes, some of whom were seriously ill.
They reminded organisers that alcohol consumption was strictly banned on the Champs de Mars, a large green space between the Eiffel Tower and the Ecole Militaire training academy in central Paris.
Organisers of giant drinks parties portray them as an inspiring way of using the Internet to bolster real-life social interaction.
"Young people are engaged in real encounters instead of virtual contacts," said Christophe Moreau, a sociologist at Rennes University.
Not everyone sees them that way though.
Local authorities in the town of Foix and the city of Montpellier decided to ban parties scheduled for April, citing a high risk of public disorder.
Green party members in Montpellier however stepped forward and said they were ready to act as co-organisers of a giant drinks party and take the necessary steps to maintain order.
That party is scheduled for next Wednesday.