Mayor Christian Estrosi of Nice, France, presented one of the birth certificates of Angelina Jolie and Brad Pitt's twins on the steps of Nice's Fondation Lenval hospital, where son Knox Leon and daughter Vivienne Marcheline were born Saturday, PEOPLE reports

Mayor Makes Vivienne Marcheline and Knox Leon Births Official

The typed certificate revealed that Knox was born at 6:27 p.m. on July 12. Sister Vivienne came within a minute of that time, Dr. Michael Sussmann tells PEOPLE.

The document also showed the Mayor's signature, as well as Pitt's initials, the letters WBP representing his full name, William Bradley Pitt.

The mayor entered the hospital at 3:24 p.m. to oversee the signing, telling PEOPLE, "It's a pride to Nice and all its citizens."

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