Fanfiction.net is also a great place to search. There are many authors who write about this pairing. However, the quality can vary, so you might need to read through a few to find the ones that really suit your taste. Look for ones with high ratings and positive reviews.
Another option is to join some Harry Potter fan communities on social media platforms like Reddit or Tumblr. People often share their favorite fanfictions there, and you can ask specifically for Hermione and Fleur romance fanfics. Some members might even have their own collections or recommendations.