A Sag Harbor coffee shop shuttered for months because of fire damage was cited for illegally expanding just two days after reopening this month, an official said.

SagTown Coffee combined space with a neighboring storefront without full approval from the village planning board when it opened Aug. 5, building inspector Thomas Preiato said Monday.

The popular coffee shop had permission to convert the former space of Collette Luxury Consignment into a coffee shop, Preiato said. But its planning board application to merge the units is still pending.

Preiato said he approved SagTown’s certificate of occupancy on Aug. 3, when there was still a wall separating it from the consignment shop. But when SagTown reopened two days later, the wall was no longer there.

The coffee shop now sells merchandise, including T-shirts and thermoses, in Collette’s former retail space.

Preiato said he cited SagTown on Aug. 7 for violating the certificate of occupancy and for not having site approval from the planning board.

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Tisha Collette, who co-owns both SagTown and Collette with her husband, Shane Dyckman, said they renegotiated their lease with landlord Sag Harbor Venture LLC to allow the expansion.

Collette, who recently relocated the namesake store to a pop-up shop at Bridgehampton Commons, said she believes the dispute will be resolved soon.

“Being in the Hamptons, there’s a lot of requirements to keep things a certain way, and it’s just a part of doing business,” said Collette, who also owns shops in Manhattan and Southampton Town. A SagTown coffee shop also operates in Montauk.

The SagTown in Sag Harbor is one of the few businesses to reopen in the same spot after a Dec. 16 fire tore through the downtown and damaged or destroyed five buildings, including the Sag Harbor Cinema. Most affected businesses are either still closed or have moved elsewhere.

Collette said that while the coffee shop sat empty for months, construction to rebuild “happened very quickly” once a building permit was issued in April.

Collette and Dyckman could face fines of up to $1,000 and up to 15 days in jail per violation.

They are scheduled to appear in Sag Harbor Village Court on Sep. 19.