avoir une mémoire d'éléphant

To have an excellent memory

This expression describes someone with an exceptional memory who can remember details from long ago.

Marie a une mémoire d'éléphant, elle se souvient de tous nos anniversaires sans aide.

Marie has an elephant's memory, she remembers all our birthdays without any help.

Based on the elephant's renowned ability to remember routes and recognize other elephants after years apart. The observation goes back to ancient times.