Two legendary downtown hotspots celebrated the Nineties together on Sunday night. Angie Mar of the shuttered Beatrice Inn and Jean-Marc Houmard of Indochine hosted a bash at his Noho fixture, with Mar reviving some of her menu in the Indochine kitchen for one-night-only. Guests reminisced while enjoying the Beatrice’s Le Burger and favorite dishes from Indochine, which opens its doors in 1984. The French-Vietnamese restaurant — recently featured in JFK Jr. and Carolyn Bessette show “Love Story,” which has sparked a fad for all things 90s — saw some of its heyday in the decade. The hotspots co-owner Houmard told us one of his favorite memories was a 50th birthday bash in 1992 for Grace Coddington, former creative director at-large of Vogue, thrown by Anna Wintour. Jean-Marc Houmard of Indochine teamed up with former Beatrice Inn owner Angie Mar for a one night collaboration. Sidewalkkilla “It was all the supermodels,” Houmard told Page Six. “It was an amazing party.…