Montreal police are investigating a major fire that broke out early this morning in a century-old building in Old Montreal, leaving at least one person in hospital.

Authorities say the fire is believed to have started on the ground floor and the cause is unknown, but police have taken over the investigation because the blaze is considered suspicious.

Apart from one person hospitalized with burns, a second person was treated for shock but did not need to be hospitalized.

About 125 firefighters were deployed to the scene, and smoke could be seen billowing from the building for several blocks in the city's historic district.

Fire broke out about 2:40 a.m. on the ground floor of the building, which houses a restaurant, with the upper floors used for short-term rentals.

According to the City of Montreal's property assessment roll, the Notre-Dame Street East building was constructed in 1923 and is owned by Emile Benamor.

Benamor is also listed as the owner of a heritage building nearby that was ravaged by fire in March 2023, leading to the deaths of seven people.