Fashion student Pauline looked as chic as ever in black trousers, a sheer black top and boots. The royal completed her look with an elegant white blazer and added a pop of colour with bright scarlet lipstick.
Along with her mother and aunt, 19-year-old Pauline also proudly sported the circus' souvenir scarf.
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Princess Charlene, 35, opted for an all-black ensemble while 48-year-old Stephanie who chaired the event, teamed dark trousers with navy top that was embellished at the collar.
The foursome then posed with the show's stars including trapeze artists, acrobats, jugglers and clowns.
The International Circus Festival is well loved by the Monegasque leaders who are annually invited to attend the opening night.
The ten-day show, which is now in its 38th year, was founded in 1974 by Albert and Stephanie's father, Prince Rainier, who was grandfather to Pauline.
Over the past year Pauline has been increasing the number of royal engagements she has undertaken with Princess Stephanie.
In December the mother-daughter duo stepped out at an auction held in Monaco on World AIDS Day to help raise funds for Princess Stephanie's foundation.