Convention traffic and street-clogging protests may have stifled sales for some city businesses, but it seems nothing can stop the promise of tax-free shopping.

The first day of a weeklong tax exemption brought shopkeepers a reprieve from the traditional late-summer sales snooze, which many say has been exacerbated by hassles created by the Republican National Convention and the mass demonstrations that have arrived with it.

Many stores used large window displays to promote the removal of the 4.25% state sales tax on clothing and footwear purchases up to $110. The exemption runs through Monday and was approved earlier this summer by the Legislature.

Except for back-to-school shopping, late August is usually a slow week for Manhattan retailers, and many store managers and employees said the tax-free promotion offered a significant boost in sales yesterday.

“More customers are definitely coming in than last week,” said Idelisa Lopez, a saleswoman at N.Y.F.H., which sells women’s clothing on Broadway across from City Hall Park.

At Golden Touch on Church Street, owner Terek Abdelkadr estimated a spike in sales of 20% for the day because he advertised the lack of sales tax on clothes.

“It’s been very bad,” Mr. Abdelkadr said, referring to the convention and protests, which he said had slowed business. “But today is better than yesterday.”

The occasional tax holidays have had a combative history in state politics since the Legislature approved the first week-long break in 1997. Lawmakers made the exemption permanent in 2000 but reinstated the tax in 2002.

Many legislators promised to remove the clothing sales tax again last year, but put it back in during the budget process. The Legislature finally decided in June to have two tax-free weeks, one now and another at the end of January.

The latest decision drew the ire of the Retail Council of New York State, which supports the exemption but said lawmakers took too long to inform businesses of the duty-free week.

“Retailers need more time to create their promotions,” said the council’s spokeswoman, Rebecca Marion. Still, she said the council expects the tax break to be successful.

“We really think people were waiting for the tax holiday,” Ms. Marion said. “We’ll see what happens, but we’re optimistic.”

The state Department of Taxation and Finance is expecting consumers to save a total of $75 million in state and local taxes, but there are no projections for how well businesses will fare.

The City Council speaker, Gifford Miller, earlier this month called for an extension of the tax break for businesses within a 31-block radius of Madison Square Garden, the site of the Republican convention.

Many businesses there have reported a significant drop in sales because of convention traffic and large demonstrations. The extension did not go through, but a spokeswoman for Mr. Miller said he will be meeting with local business owners tomorrow to assess the impact of the convention and the sales-tax break.

Politics aside, most shopkeepers are just grateful for the added customers.

“I didn’t even remember” about the tax exemption, said Shirla Yam, the owner of City Apparel on Murray Street. “But I do have more than yesterday.”