SHANGHAI - A new downtown pizzeria is being investigated for causing offence by advertising its location as "in the French Concession", although the term is used by many other restaurants.

The British pizza chain Marzano is said to have outraged local residents with promotion leaflets naming the area of its newly opened branch in Xuhui district as the French Concession.

Law enforcement officers of the municipal market watchdog went to the restaurant at the weekend and are continuing their enquiries.

Laws require that no advertisement touches on discrimination of nationality, race, religion or gender.

Many people online expressed their distaste at the use of the colonial expression.

"I don't regard 'the French Concession' as a graceful expression. They'd better learn about Chinese history and not hurt Chinese people's self-esteem," a micro-blogger named "DearT-Tspiritualist" commented on Monday.

The city's French Concession existed from 1849 to 1943, covering the main residential and retail areas in Xuhui and Luwan districts.

But several other businesses also have been advertising their location as being in "French Concession".

El Gato Verde, a Mexican restaurant, claims it is a "French Concession favorite" on its website.

"It has nothing to do with politics, but only makes it easier for foreigners to locate the restaurant," said the restaurant manager, who gave her name as Zhao.

Other venues, including O'Malley's Irish bar and Guxi Hunan Restaurant, also claim to be in "the French Concession" in their online publicity.

The pizzeria apologized on Sunday for informing customers of the address in this manner.

"Pizza Marzano comes from Britain and the management team is formed of British people who are unfamiliar with Chinese culture. We didn't intend to offend nationalist sentiments of Chinese people, and we felt truly sorry," the pizza company stated on its micro blog.

All promotion leaflets had been withdrawn on Feb 21, they said, after a customer surnamed Yuan complained about the wording.

The pizzeria branch manager emphasized that they did not intend to offence, and said they promoted it in this way only because the term was widely recognized among expats.

"Foreigners may not have clear idea of street names, but they will know if we say we're in the French Concession," said the restaurant manager, who declined to give his name.

Helen Boyle, an architect who has been working in Shanghai for eight years, agreed that the term was widely used by expats to describe the downtown areas.

But Shanghai University sociology professor Gu Jun said the matter was more complex.

No wrong is done looking at it in the cultural context, Gu said. "But the pizzeria did make a mistake if we look at it politically, because the land was ceded back a long time ago."

"The Bund, which is also a remnant of the shameful colonial days, is the No 1 scenic spot for tourists to Shanghai. Surely it doesn't mean that we have to pull down the buildings?"