The inferno, the deadliest in the city since the liberation of Paris by Allied forces during World War II, gutted the Paris-Opera Hotel in April 2005.
The hotel, which housed many struggling immigrant families, was located just behind the upmarket Galeries Lafayette department store, a landmark in the French capital.
"Your characteristic carelessness directly caused the death of 24 people," the judge told Fatima Tahrour.
"It is highly probable that at the very least you were aware that the fire had started."
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Tahrour has admitted accidentally causing the fire when in a fit of anger she flung her clothes on candles on the floor and then left the building.
Tahrour, her then-boyfriend Nabil Dekali who was the nightwatchman on duty the night of the blaze, and his parents Rachid and Fatima, who managed the building, went on trial in November.
Dekali had taken cocaine and alcohol and is accused of not contacting firemen immediately and trying to douse the flames himself.
The court sentenced Dekali to two years in prison, with one year suspended, saying that the drugs and alcohol had "altered your reflexes," adding that he had "lost precious time" by not calling the fire service immediately and later disrupted the rescue work.
The judges ruled that Rachid Dekali was "perfectly aware of the son's drug addiction and therefore aware of the danger of putting him in charge of surveillance of a hotel that was overpopulated."
There were too many people in the hotel with 77 crammed in a building that could legally only house 62.
Firemen who arrived at the building described an "apocalyptic scene", with bodies having "rained down on the street, and panicked people throwing children out of windows".