The one-and-a-half-year-old, 200-kilo tigress, Mevy, was shot dead after people spotted her wandering through the streets of Paris's 15th arrondissement on Friday evening.
She had escaped from the Bormann-Moreno circus and its owner, Eric Bormann shot her within a few minutes of her escape.
He used the firearm he is required to carry by law as the owner of a potentially dangerous beast.
Using a tranquilliser gun was ruled out because of the time it takes for the sedatives to work, Bormann said.
Police questioned him for several hours after the incident.
Bormann said on Saturday that the animal's cage had been cut open in a "malicious act" and has asked police to investigate.
An investigation has been launched into whether lives were put in danger.
The circus, which has several tigers, had just set up and planned to open its doors to the public on 3 December.
Live animals in circuses are already banned in 29 countries worldwide and in 63 French towns and cities.