The rats are so bold they run on to the grass in broad daylight, scaring tourists visiting the site.
The hot weather in Paris has brought out many picnicking visitors, whose rubbish left in the garden is a feast for the rats.
Jean-Claude Ndzana Ekani, a museum employee, said the vermin have also been helped by animal lovers who dig up the poison and "give water to the rats".
The lush area which extends into the Tuileries Gardens gives the rats plenty of places to hide, but still they run scamper openly.
One tourist, Dutch woman Evelyne Delemarre, 31, let out a piercing scream when a rat scampered by her.
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