UFC-Que Choisir said a late-December poll of 80 three- and four-star hotels showed that on the night of July 26, the day of the Olympics’ opening ceremony on the banks of the Seine river, a double room will cost €1,033 (US$1,128) on average, compared to €317 two weeks earlier on the night of July 12.

It also said 50% of these hotels reported being already fully booked that night, while 30% required a minimum booking of at least two nights and some as many as five nights.

The average required minimum stay was 3.4 days, for an average cost of €867 per night, UFC added.

“Olympic room rates! Paris hotels are not holding back, their room rates are on fire,” UFC said.

It said one three-star hotel had hiked its price for a double room to €2,083 compared to €304 two weeks earlier, while one four-star hotel required a minimum booking of four nights at €2,095 per night.

Paris’s tourism office expects some 16 million people to visit the wider Paris region for the Olympics and Paralympics, putting pressure on every level of the housing and hotel market.

Airbnb has called on Parisians to put up their homes for rent during the games in order to keep prices down.

North of Paris, in the Seine-Saint-Denis area where the Olympic Village is under construction, thousands of migrants, asylum seekers and Roma squatting empty buildings have been evicted, aggravating the city’s homelessness problem.

The games will run from July 26 to Aug 11.