Cut the fish into pieces then chop it with a knife quite coarsely, set aside in the cold.
In a pan, sauté the small seeds over low heat for 5 minutes.
As soon as these seeds are cold, mix them with the fish. Season with salt and pepper and drizzle with olive oil. Film your preparation and put it in the fridge.
When ready to serve, arrange and divide the tartare among the cold plates, place a few green radish sprouts on top.
Garnish with a slice of lemon.