Montague Street in Brooklyn Heights is dotted with diners, coffee shops, bakeries and restaurants, many of which offer outdoor seating for customers who frequent the street, pushing strollers or walking dogs.

The Grand Canyon Restaurant is no different. Gonzalo Carreto, the diner’s owner, said he had erected an outdoor dining shed during the height of the pandemic, when eating outside was sometimes required and often preferred, but that recently he had opted for just a few tables and chairs on the sidewalk.

Early this month, an inspector with the Department of Transportation stopped by and told Mr. Carreto to remove the outdoor tables, which he did. He asked if the seating next to the restaurant’s front door, under its awning, could stay. The inspector told him that was fine, Mr. Carreto said.

But a few weeks later, another inspector arrived and fined Grand Canyon $500 for its four remaining tables.

While Mr. Carreto was shocked, his experience is not uncommon as New York City transitions into a new era of limited outdoor dining, four years after tents, huts and sheds sprang up across the city to meet customers’ growing demand for fresh air.

As the city instituted sweeping new rules earlier this year to address the dining sheds that proliferated during the pandemic, it also tightened the regulations governing the use of sidewalk seating.