Fearing a second wave of the novel coronavirus, Amsterdam is calling on tourists not to visit the city at weekends.
Visitors should rather postpone their visit to Monday or to Thursday, the city said on Thursday.
"Appeals are now being made on social media to anyone considering a visit to Amsterdam to avoid the weekend crowds and to plan their trip during the week," the city said in a statement also released in English.
"Most areas of the city are still less busy on weekdays than at the weekend."
Tourists who are already in the city are asked via social media to observe the coronavirus rules and to avoid crowds in the city.
No alcohol is allowed to be sold throughout the weekend in shops in the red light district. The ban does not apply to pubs and restaurants.
Comply with social distancing
"The reason for the ban is that people who buy alcohol in shops and consume it in the street are less likely to comply with the 1.5-metre rule and can pose a threat to enforcement officers when addressed about their behaviour."
The influx of tourists, particularly from Germany, Belgium and France but also from the Netherlands, has increased so that the prescribed safe distance of 1.5 metres cannot be maintained in the city centre.
The city had previously declared the red-light district and the main shopping street Kalverstraat a one-way system for pedestrians.
Nevertheless, last weekend it was so crowded where the prostitutes offer their services in windows that some canals and alleys had to be closed off.