A possible plot could be that after the war, Harry is in need of a fresh start. Fleur, who has always been attracted to his heroic nature, offers him a chance at a new life in France. Their marriage is a journey of self - discovery for both of them. Harry learns about the different wizarding traditions in France, and Fleur gets to know the more reserved side of Harry better. They build a relationship based on mutual respect and the shared goal of creating a peaceful future for the wizarding world.
One interesting plot twist could be that the marriage contract was actually a ruse by a dark wizard to gain control over both Harry and Fleur. So they have to team up to break the contract's hidden enchantments.
One interesting plot could be Fleur and Harry teaming up for a dangerous magical quest that was previously thought impossible. They could use their unique magical skills, like Fleur's Veela charm and Harry's Parseltongue ability, to overcome various obstacles.
One idea could be that Harry and Fleur travel back to the time of the founders of Hogwarts. They could witness the creation of the houses and perhaps even influence some of the early magical traditions. For example, they might help Gryffindor and Slytherin better understand each other, which could have a huge impact on the future of Hogwarts and the wizarding world.
In this type of fanfiction, it might also delve into the reasons behind Harry's actions. Perhaps he's under some sort of magical influence that makes him act this way. Or it could be a case of miscommunication and misunderstanding that leads to this situation with Fleur. It could show how easily relationships can be strained in the wizarding community.
A possible plot could be that Harry Potter discovers a prophecy that involves Fleur and a powerful vampire. The prophecy states that only together can they defeat a new dark force rising. Along the way, Fleur has to struggle with her own identity as she is part Veela and now has vampire traits after an encounter, and Harry has to deal with the mistrust of the wizarding community towards Fleur's new state.
Perhaps in the fanfiction, Fleur could be in danger during one of the Triwizard Tournament tasks. Harry, being the heroic type, decides to risk everything to save her. This act of heroism not only changes their relationship but also how the other champions and the judges view Harry. It could also lead to some changes in the overall dynamic of the tournament, like new rules being implemented to prevent such dangerous situations in the future.
One idea could be exploring their wedding planning and all the chaos that comes with it. Maybe Molly Weasley is over - involved and wants everything to be perfect, while Ginny just wants a simple ceremony. Another could be their first year of marriage, dealing with things like living together in a new home and adjusting to each other's habits.
One idea could be that they are forced into an arranged marriage for political reasons in the wizarding world. They start off hating each other but gradually discover they have more in common as they deal with the challenges together.
One idea could be that they start off as enemies but are forced into a marriage by some magical law. As they live together, they gradually discover each other's hidden depths and develop a grudging respect that turns into love.
Well, perhaps a plot twist is that the marriage contract was actually a misinterpretation all along. It was originally written in an ancient magical language that was misread, and instead of a marriage contract, it was a pact for magical knowledge exchange. So, Harry and Fleur have to figure out how to deal with this new understanding and the expectations of their families and friends. It also might be that the contract was magically altered by a dark wizard long ago, and as they dig deeper into it, they uncover a conspiracy that dates back generations.