Barcelona (AFP) - A faint smell of cannabis smoke hangs in the air as Susana relaxes on the sofa with her mother Juana and lights up a joint.
Welcome to Pachamama -- one of the hundreds of cannabis clubs that are making Barcelona rival Amsterdam as a smoker's haven.
With shelves full of books and board games the place could be someone's sitting room, but for a hookah pipe and photographs of hemp plants like the ones the club grows.
"This is the safest way to know what I am smoking and at the same time avoid participating in the black market," says Susana, a 27-year-old shop assistant with her curly hair dyed red.
Smokers' groups say some 700 such associations have sprung up in Spain due to a legal loophole.
Dealing in cannabis is illegal in Spain but the law does not penalise growing it for private consumption nor setting up smokers' associations.
Now authorities are getting concerned, however.
Barcelona's city hall has imposed a moratorium on associations opening premises for smoking the drug and regional authorities also want new rules on cannabis.
"These clubs have spread due to a lack of regulation," said Antoni Mateu, head of public health in the Catalonia regional government.
"Our priority is to discourage consumption, but a regulation is required to curb it."
Half of Spain's cannabis clubs are in Barcelona, which tops the rankings on WeBeHigh, a travel advice website for soft drug users.
There are also many clubs in the northwestern Basque region, whose regional government has announced it is drawing up new regulations for cannabis use.
"Since it is not regulated, it is not legal," said Jaume Xaus, spokesman for the Catalonia Federation of Cannabis Associations.
"But no one knows either what paperwork you have to have nor how to prove to the police, if they come, that what we are doing is not breaking the law."
- Cannabis-conscious -
For two years now Susana has come once a week to Pachamama to buy five grammes (just under a fifth of an ounce) of marijuana. She sometimes brings her parents along too.
"You have to consume responsibly and be conscious of what it entails," she says. "But it is the same with medicine, alcohol and tobacco."
Would-be members must be over 18 and be recommended by an existing member. They must be able to show they are habitual smokers.
The club's 186 current members pay an annual subscription of 10 euros ($14) plus a variable fee to cover the cost of producing the cannabis they consume.
"This is not a potheads' club," says Patricia, 28, who founded Pachamama in 2012 in Barcelona's trendy Gracia district.
Like the other members, she asked not to be identified by her surname.
"Here we control the consumption," she said. "We inform members about the effects of smoking and we ensure a quality product," she adds.
"We have nothing to hide. We are not doing anything wrong."
A cannabis club is legal as long as it controls consumption and refrains from advertising and distributing the drug for profit, said penal law specialist Juan Munoz.
Some clubs are suspected of stepped over the line, however, venturing beyond their non-profit association activities into full-blown drug-dealing.
"Some cases have been discovered of clubs promoting consumption among tourists, supplying to traffickers and minors," Mateu said. "Some have also had problems with the neighbours."
Martin Barriuso, spokesman for the Spanish Federation of Cannabis Associations, acknowledged that some "bad practices" have emerged.
"We have reported them," he said. "But it is hard to control without a clear regulation that separates the wheat from the chaff."