1.Heat oil in a large, heavy-based saucepan on medium. Sauté onion carrot and celery 4-5 minutes, until tender. Stir in curry powder and cayenne. Cook, stirring, 1 minute, until fragrant.
2.Add wine and bring to the boil. Boil, uncovered, 4-5 minutes, until liquid reduces by half. Add stock and return to the boil.
3.Add mussels. Cook, covered, 2-3 minutes, shaking pan occasionally until shells open. Mix in crème fraîche and parsley. Bring to a simmer, stirring.
4.Divide mussels among large serving bowls. Ladle soup over. Serve accompanied with fries.