PARIS — Another day — and another worrying statistic for Paris: The most visited city on earth stands to lose as much as $1.5 billion in tourist revenues this year.

That dire warning comes from the Paris Regional Tourist Board, which on Tuesday reported a 6.4 percent drop in overnight visitors in the first half of the year.

The tally reflects one million fewer tourists to the French capital, with foreigners accounting for almost two-thirds of the lost revenues.

It blamed a string of deadly terrorist attacks in Paris, Brussels and Nice; a spate of strikes, and the wettest spring on record in 150 years.

Europe’s luxury players, which have expanded their presence in the French capital in recent years, are sure to put pressure on government officials to stem the slide.

Exane BNP Paris has estimated that Paris accounts for 74 percent of luxury consumption in France. Only New York generates more spending in personal luxury goods than Paris, with London in third place, according to 2014 data from Altagamma and Bain.

Frédéric Valletoux, president of the tourist board, called the “unprecedented” fall in visitors an “industrial catastrophe” and urged Jean-Marc Ayrault, France’s minister of foreign affairs, to gather local tourism professionals to develop an emergency action plan.

Half-a-million jobs in Paris hinge on the tourism sector, with the region receiving about 30 million visitors annually, according to board estimates. France welcomes about 84.5 million foreign visitors a year, ahead of the United States at 75 million and Spain at 68.2 million.

According to the tourism board, visits by Japanese tourists in the first six months of the year plummeted 46.2 percent, Russians 35 percent, Italians 27.7 percent, Chinese 19.6 percent and Americans 5.7 percent.

Even the French shunned the City of Light, with visitor numbers easing 3.5 percent to 8.3 million.

“The whole tourism chain was strongly impacted,” the board warned, listing hotels, museums, monuments, cafes, restaurants, department stores and tour operators.

For example, entries fell 43.9 percent at the Grand Palais, 34.8 percent at the lArc de Triomphe and 16.3 percent at Versailles.

The only bright spot in the first half were business travelers, which accounted for 3.1 million nights of accommodation, up 14.4 points and accounting for 53.8 percent of all hotel revenues.

The tallies in the Paris region follow a report earlier this week by the National Institute of Statistics and Economic Studies, or INSEE. It concurred that the decline in foreign visitors is accelerating, with overnight stays falling 8.7 percent in the second quarter versus 2.7 percent in the first.