Wait, you are talking maybe about heroin addicts beyond saving. But if you just want to buy some weed, you definitely must go to shady characters standing on corners of dark streets in the night, and buy overpriced at-best-mediocre-quality stuff from there (I am not racist or anything, but 100% of them in Geneva are black - that's 5 years of experience). Police guys are constantly patrolling these areas (often with dogs), dealers are super suspicious that you are an undercover cop etc.
if you get caught with tiny amount (< 1g) at the border, you will face harsh fine, full body cavity inspection etc.
Nah, this country is definitely not a paradise, just there are worse places.