Preheat the fryer. In a large saute pan with a lid, heat the olive oil. When the pan is hot, add the onions and fennel. Season with salt and pepper. Saute for 2 minutes. Add the tomatoes and garlic. Season with salt and pepper. Saute for 1 minute. Add the wine, cream and saffron. Bring the mixture to a simmer. Add the mussels and parsley then cover. Simmer for 4 to 6 minutes or until the mussels open. Discard any shells that do not open. Fry the potatoes in oil until golden brown. Remove and drain on paper towels. Season with salt and pepper. To serve, spoon the mussels into a shallow bowls and serve the frites on the side.