What if you get stopped by the Police on the streets of Barcelona, smoking or carrying dope?
It is not only against the regulations, but it is in fact very difficult to challenge.
First of all, whereas use of drugs is not illegal per se, the consumption or possession in the street or public areas is deemed an act against regulations and, as such, subject to a fine up to a minimum of € 601.
Second, take this into account:
Should the Police stop you, and see you carrying drugs (or find some in your pockets or belongings), they can give you a ticket for that minimum amount (and that is for the first offence –see below).
If the quantity exceeds what regulations deem the average quantity for own consumption, you might be arrested under suspicion of trafficking. In this moment, the issue becomes a criminal matter, and you would most likely be taken to Court.
“Sharing” could be interpreted as trafficking. In any case, the fine would be unavoidable. Again, it could become a felony and be taken to Court.
Third: Many people think that, being an administrative offence, it is easier to challenge and reduce (or cancel) the fine. In reality, it is expensive and takes a long time. If the allegations are not heard by the administrative authority, there is no remedy but appealing before the Court. Procedure takes years.
Fourth: yes, the Police can stop and frisk you searching for drugs. Yes, you could challenge that afterwards –usually, on grounds of no objective reason or suspicion-, but you cannot object to the search without risking being arrested.
Additional note: the second time somebody would get fined for this subject within a 2-year period, the amount could add up to a minimum of € 10,421 (yes, more than ten Thousand Euros).