The Notre Dame Cathedral is a medieval cathedral located in Paris, France.
World of Winx
In "The Alligator Man," Bloom, Stella and Musa head to Paris in the hopes of finally finding Peter Pan's son, Matt Barrie, after uncovering the secret hidden within the fresco mural they found on the Concert Hall ceiling. More specifically, they hope to find Matt at the landmark that lined up with the brightest star in the mural: the Notre Dame Cathedral, however, they are quickly swarmed by their French fans upon arrival, so Bloom tasks Musa with locating the Cathedral on her own as they keep the fans distracted.
Once night falls, Musa quickly finds Notre Dame and continues towards it, hoping to find Matt there, while being completely unaware of her Nemesis following closely behind her. Musa lands on top of the Cathedral with ease and begins her search, only to be met by a mysterious curly-haired boy wanting to know who she is. Taking notice of the small telescope-looking device in his hands, Musa asks if the boy is the Matt she and the Winx have been searching for, and the boy responds by asking how she knows his name. Musa then begins to approach Matt claiming that she just needs to talk, but something from behind Musa startles Matt and causes him to hop the ledge and run off. Rather than chase him, Musa uses her new Onyrix Power, her Sound Harmony, to keep track of Matt's movements through his footsteps and does so with relative ease until Banshee emits her own disruptive soundwaves that ultimately cause Musa to lose sight of Matt. Musa is then attacked by Banshee and has to maneuver the Cathedral's rooftop to avoid her Nemesis while calling for help.
In "Mermaids on Earth," Musa and Banshee's battle continues. Bloom and Stella arrive at the Cathedral to aid their friend after getting her distress call. The two are quickly knocked out, however, after taking a direct hit from one of Banshee's supersonic screeches before Musa could warn them. Musa is then hit by the same attack and, just as all seems lost, she discovers Banshee's weakness and uses the bells of the Cathedral to play a melody until Banshee explodes. With Banshee gone, Musa rushes to the tree Bloom and Stella fell onto to help them up and tell them of the good news. Flora, Aisha and Tecna soon regroup with Musa, Stella and Bloom, making it clear that they took care of the problem in Neverland. Unfortunately, the Winx have no time to rest as the Spirit of the World of Dreams quickly whisks them back to Neverland to assign them a new mission: tracking down a trio of mermaids who fled their lagoon and are now roaming around in Paris.
In "The Girl in the Stars," Matt leads the Winx back to Notre Dame to show them the meaning of the phrase printed in his parchment: a stone carving of a young boy looking out to a couple of stars with a small telescope. Using Matt's kaleidoscope, Bloom looks towards the second star in the stone carving and sees the image of a beautiful girl looking sad and forlorn. As Bloom comments on her beauty, Matt confesses to having fallen in love with the image, as he had been coming to the Cathedral for quite some time just to admire her beauty. However, he cannot shake the feeling that none of this may even be real, which causes the Winx to tell Matt all of the details of their magical mission, which included their true identities as fairies and the existences of both the World of Dreams and Peter Pan—the true identity of Matt's father. After being told all of this, Matt gets the idea to scour the world for its most beautiful flower to give to his beloved and disappears into a familiar blue light and portal, leaving the Winx in total shock.
Following Matt's disappearance, the Winx quickly search the perimeter of the Cathedral in the beginning of "A Flower in the Snow." Unable to find him, the Winx regroup and leave for Neverland to ask if any of their allies have seen Matt come through.