Nadar Kessard, better known as the Health Inspector, is the tertiary antagonist of Ratatouille.
Unlike most Disney villains, the health inspector's antagonism is not based on outright hatred for the protagonists, but rather performing the job he was hired to do: inspecting restaurants for cleanliness standards. When the rats are going to get him, they used coils of rope, tied him up and put him in the food closet, along with a later captured Chef Skinner. In the final scene, Remy says that there was no way the rats could have kept Skinner nor the health inspector detained indefinitely, and later had to free both of them.
Skinner calls the health inspector on a public phone outside Gusteau's to report a rat infestation. The inspector replies with him coming to check the restaurant in three months time. Skinner protests but the inspector promises a sooner visit if someone else cancels an inspection. When Skinner tries to protest again, the inspector hangs up on him.
On the next day, before Remy and the other rats start cooking, the inspector comes in the reastaurant, dropping his documents. Stunned by what he saw, he ran to his car, with Django and some other rats covering the entire car while he tries to start the car. The car eventually starts, but crashes afterwards when Colette returns. Then, the health inspector is seen tied up and being thrown in the food locker by the rats. Near the end of the film, Remy says they could not keep the health inspector (nor Skinner) imprisoned in the food locker forever and were forced to release both of them, which ultimately led to the closure of Gusteau's for health violations.
The inspector said that he will come within three months, and if someone cancels one inspection, he'll slot Skinner in. However, he comes to the restaurant on the next day, assuming the fact someone canceled the inspection.
According to Ratatouille: The Junior Novelization, his real name is Nadar Lessard.