Aboard the Mississippi Boat, moored off the banks of the Maas river, the management has suddenly come over publicity-shy. 'No interviews in here,' says a burly, long-haired man propping up the bar, 'we don't have anything to do with journalists.'
One of Holland's most popular, cannabis-selling coffee shops, the Mississippi Boat serves several hundred thousand people each year making its stream of customers the envy of many a Dutch retailer.
But Holland's famously liberal drug policy is about to confront its biggest challenge in decades. The council in Maastricht plans to make it technically illegal to serve foreigners in the city's 16 coffee shops, a move that could drive many of them out of business. If the policy is upheld in the courts, it could, eventually, be extended nationwide. The idea is just one of three controversial " and contradictory " schemes designed to curb the social problems produced by Holland's unique drug laws. Their fate is likely to determine the future of Dutch policy towards cannabis.
The fact that these experiments are taking place in this, historic, city is no coincidence. Within easy driving distance of Belgium, Germany and France, Maastricht has proved a magnet for smokers eager to take advantage of liberal laws. In their wake a trade in illicit cannabis and harder drugs has grown up, accompanied by a rise in crime.
Spurred on by complaints from police and residents, the Mayor of Maastricht, Geerd Leers, has decided that enough is enough. If Mr Leers gets his way, a new by-law will soon require all those who visit coffee shops to show identity cards proving that they are residents. Initially, the law will be enforced only in one coffee shop which will, if necessary, take the case all the way to the European Court of Justice. But, if it loses, foreigners could be banned for all 750 coffee shops in the Netherlands.
In Maastricht's sprawling modern, municipal, headquarters they have been debating for years how to deal with the special effects of the country's drugs policy on a border city. Though they still support the principle of legalising limited use of cannabis, they believe bold steps are needed to tackle its unwelcome consequences here.
Ramona Horbach, one of the Mayor's two drug advisers, argues: 'People who visit Maastricht are responsible for a lot of problems, from parking problems to urinating in the streets. There is intimidation, there are efforts to persuade people to buy [hard] drugs. They are trying to sell cocaine, ecstasy or heroin.' Most of the coffee shops are to be found in the relatively small, historic, centre of the city, concentrating the problems in one, compact and highly visible zone.
But a small number are in other neighbourhoods, provoking local opposition.
Ms Horbach's colleague, Jasperina de Jonge, adds: 'Many tourists come to try to buy soft drugs here in the Netherlands that you cannot buy in Germany, France or Belgium.
'Too many people are visiting. Sometimes there is rowdy behaviour. Some of the coffee shops are in residential areas and people no longer like living there.' Parents of young children feel particularly threatened by the combination of rising traffic and a reduced sense of security.
Naturally it was not meant to be like this; the whole point of coffee shops was to bring the use of soft drugs out of the sphere of influence of the criminal gangs.
Though several nations have relaxed their laws on soft drugs, the Netherlands leads the way in regulating their sale. Coffee shops are licensed and no alcohol can be sold or consumed in them. According to the government's own guide, the policy is a success. 'Use of cannabis in the Netherlands is comparable to that in other European countries, whereas in the United States it is substantially higher,' it says.
But this has been achieved through a contradictory law. …