Paris has suffered a one million drop in tourists in the first half of the year following terrorist attacks, strikes and flooding.
The slump is estimated to have cost about €750 million in lost revenue.
One senior official described the January to June fall as “an industrial disaster”, the BBC reported.
The French capital usually attracts 16 million visitors a year and is one of the world’s top tourist destinations.
But tourism has been in steep decline since gunmen killed 130 people in November’s terrorist outrage.
The city was only just recovering from an attack in January 2015 on the satirical magazine Charlie Hebdo.
Tourist board figures show that nightly hotel stays were down 8.5% in the Ile-de-France region in the first half of 2016, with an 11.5% decline in foreign tourists and a 4.8% decline in French travellers.
The figures show a 46.2% year-on-year decline in Japanese visitors, a 35% drop in Russian arrivals, 19.6% from China and 5.7% from the US.
Paris region tourist board head, Frederic Valletoux, said: “It’s time to realise that the tourism sector is going through an industrial disaster.
“This is no longer the time for communication campaigns but to set up a relief plan.”
He called for major investment to protect jobs in the tourism sector and government and trades union action to address the problem.