Note: I haven't watched this French film but I found a summary on IMDB. That is enough for this story. Not 100% Canon.
Mario is a simple man. A gay barber, he dreamed of being a singer. His life was simple. Get up, work and help his family. His stepmother Teresa, his sister Carolina and his father Maurice. Until the day he heard a wonderful voice singing. A woman's voice.
Mario meets Marie-Hélène, a pregnant woman dressed in white. She claims to be the Virgin Mary. Mario's family has always been very religious. Although the barber doesn't think she's the Mother of Jesus, he takes pity on her. Thus he introduces her to his family. They all fall under her spell and she's allowed to stay with them. Even Mario feels attracted to her even though he's gay. Perhaps it's because he sees his dead mother in her.
Marie-Hélène is changing, disrupting everything around her. Teresa starts talking to a chandelier to reconnect with a former lover. The pregnant woman had told her that his soul was inside. Teresa believed her. Carolina, who had always felt weak and prey to mockery, feels invincible with Marie-Hélène's support and she beats people up without any remorse. Maurice thinks that his son isn't gay after all, that he's going to get married and start a family according to Marie-Hélène's opinions. And what about Mario?
He finally believes her. She is the Virgin Mary. She has chosen him for a mission. To spread her Truth to the whole world. Even if it's dangerous, even if it could kill him, Mario is ready to do anything for her. He's blinded by her beauty, despite her apparent wickedness and the harm she's doing to his family.
Mario desires her, loves her, even though he's gay. He wants to raise his future baby with her. He hesitates to tell her how he feels. After all, is he worthy of the Immaculate Conception? Mario would break himself for her.
The day he decides to declare his love for her, the Virgin Mary laughs in his face. Mario doesn't understand her reaction. The Immaculate Conception says nothing more. For Mario, it means only one thing. He must serve her, continue her mission, and finally win her heart.
And so Marie-Hélène, victorious, stays forever with Mario and his family who are her puppets, her toys. Mario never realized his dream.