“Which one would you recommend for someone with medical issues?” she asks salesman Paul Monot, co-founder of the DrGreen shop in western Switzerland.

Posters of bright green cannabis plants advertise its wares, which, like those sold openly in a growing number of shops across Switzerland, are completely legal.

There is a catch however: They won't make you high.

“There is no psychotropic effect of our weed,” says Monot, at his store in Lausanne.

On display are four varieties of legal cannabis boasting familiar names such as Skunk and Purple Haze, and an identical appearance and smell as their illegal counterparts.

Since 2011, cannabis containing up to one percent tetrahydrocannabinol (THC) – the component that gets recreational users high – can be sold and consumed legally in the wealthy Alpine country.

That compares to a 0.2-percent limit in most European countries, which effectively blocks all sale of cannabis flowers since crossbreeding plants to consistently contain below that level of THC has so far proved impossible.

Switzerland was eager to enable large-scale production of non-drug cannabis, especially to exploit another active component, cannabidiol (CBD), used in a range of products, from cosmetics to pet food, and increasingly valued for its potential health benefits.

Taxed liked tobacco

It has taken years for the low-potency cannabis business to develop and demand to grow, but recently shops like DrGreen have been booming.

Monot and his partner launched in December and are already raking in sales of up to 100,000 Swiss francs ($99,500, €93,400) a month.

Swiss media have cited estimates that sales of legal cannabis are currently about 100 million Swiss francs annually.

Trade really took off after health authorities in February ordered the low-THC cannabis be taxed like tobacco and carry similar health warnings, making it clear just how legal the product is.

“For the past month or so, it has just been exploding,… and we're surfing the wave,” Monot told AFP.

Aziza, 37, said she only discovered a few weeks ago that legal cannabis was on sale in shops near her Geneva home.

“I love this stuff,” she said, adding she had become increasingly concerned about the rising THC-levels in the illegal product she liked to smoke.

“With this stuff, I feel the same relaxation as before, but since there is no high, I can still get things done and play with my kids,” she said.

'Sort of oasis'

Monot buys the cannabis he sells in bulk from a producer in northern Switzerland, KannaSwiss, which has also seen an explosion in sales.

“Switzerland has become sort of an oasis” for legal cannabis, said KannaSwiss co-founder Corso Serra di Cassano.

KannaSwiss counts around 10,000 square metres (108,000 square feet) of outdoor growing space and plans to soon triple the 800 square metres it has indoors.

“Demand in Europe is very big, and we're the only country at the moment that has laws that make this possible,” Serra di Cassano said.

Canada has just unveiled legislation to fully legalise recreational marijuana use, making it only the second country to do so, after Uruguay.

For many, the Swiss offer seems too good to be true.

“So this stuff is 100 percent legal?” asks a man in his 20s with several visible piercings and tattoos as he sniffs the DrGreen Skunk. “Can I smoke it on the street?”

Monot says he spends much of his time advising customers how to use his products without getting into trouble.

If police are suspicious, they can demand to test the cannabis in a laboratory for THC levels and hand the bill to the user if it is above one percent, along with a fine for illegal possession.

Monot urges the man to smoke discreetly and suggests he hold onto his receipt, pointing out that as long as the seal on the plastic container is not broken, the product inside is guaranteed to be legal.

'Calming'

The cannabis plants KannaSwiss and others specialise in are bred not only to have low THC levels but also high levels of CBD.

CBD is considered anti-inflammatory and to have numerous potential therapeutic benefits, such as for panic attacks or as pain relief.

“It really calms the nervous system, but without any psychoactive effects,” Serra di Cassano said.

Many people also buy the low-potency cannabis to help wean themselves off the illegal variety.

Legal cannabis currently sells for between seven and 18 Swiss francs a gramme, on a par with the street price for the THC-loaded illegal marijuana.

'Wild West'

KannaSwiss specialises in making CBD oil, also used for therapeutic and relaxation purposes, which sells for between 17 and 50 francs a gramme depending on its concentration.

But while that business is booming, Serra di Cassano says the regulation of legalised cannabis is not yet tight enough.

“It's a bit the Wild West,” he said, worrying that without strict controls poor-quality and even health-hazardous weed could reach the market, or that dishonest sellers could mix illegal cannabis with KannaSwiss' product.

“We would like to see (this business) continue for a long time,” Serra di Cassano said.

But he said he feared that “if people misbehave and don't treat it with respect, I don't think it will be around for very long.”