"You are dealing with a demographic, not a geography, so you need to think in nongeographic terms," Mr. Guarino said. "Some brands have 150 store locations in China alone," he said. "But their cash registers are in Europe and the United States."
Just how dependent the European luxury sector has become on Chinese visitors became starkly evident late last year. In October, China passed a consumer-protection law prohibiting travel agencies from subsidizing group tours to Europe by including mandatory stops at high-end department stores like Galeries Lafayette in Paris or La Rinascente in Milan.
Beijing considered the practice — whereby mass-market agencies used commissions from retailers to offset deeply discounted package tours — to be misleading. Mr. Sfez, of Global Blue, estimated that before the law changed, such captive buying represented roughly 40 percent of all Chinese luxury purchases in Europe.
The law had a striking effect on Chinese tourists' luxury spending in the fourth quarter, halving sales growth across the European Union to 9.5 percent compared with growth rates of 20 percent or more in the preceding three quarters of last year.
(Read more: China has a word for its crass new rich)
But analysts do not expect a reversal of the broader trend, because higher prices in China compel so many Chinese to prefer shopping overseas. Luxury handbags, which might sell for $1,000 to $5,000, cost on average nearly a third less in Europe than in mainland China, according to Renaissance Capital, a Russian investment bank. Markups by Western brands are common in China, where foreign companies must navigate a thicket of red tape to do business and pay high rents for premium retailing space.
The price gap is further widened by China's high taxes on consumers. On top of an import duty of 10 percent, Beijing levies a value-added tax of 17 percent and sales taxes that can range from 5 percent to 20 percent, depending on the item. Some other Chinese cities add taxes as well.
Foreign visitors to the European Union who spend more than 175 euros, or $236, in the same store on the same day, meanwhile, are entitled to a rebate on the value-added tax, which in most member states hovers around 20 percent.