Paul Kehoe's office in New Ross, Co Wexford, was one of two properties attacked in the town in the early hours of Friday morning.
A fire was set in a room at the back of the ground-floor office on the corner of Priory Lane and the Quays.
No major damage was done to the building which is underneath a block of apartments.
Another fire was also set at a building on South Street and a car damaged in Barrack Lane at around 3.30am.
A 21-year-old man and another aged 33 have been arrested, gardai said.
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