What you see here is "Ramson" or "Wild Garlic" ("Ail Des Ours" in French & "Bärlauch" in German), a wild relative of chives.
This plant grows mainly in humid/swampy woodlands that have acidic soils. It flowers before the trees get their leaves and fills the air with it's characteristic strong smell that ressembles garlic.
"Ramson Leaves" should not be mistaken for "Lily Of The Valley" leaves which look quite similar and which are highly poisonous, even deadly. When bruised, "Ramson Leaves" have a pungent smell of garlic, "Lilly Of The Valley" leaves don't (they smell green, that's all)...
At the moment and 'till the end of April (latest 'till the very beginning of May), you can find them easily in our woods (Geneva Area) where they grow like beserkers and cover/colonize entire areas/patches.
This plant is free, not rare at all and tastes gorgeous, so I really recommend you to visit your nearby woods and pick some of those delicious leaves in order to spice up your salads, omelets, pasta (Ramson Pesto) or aromatize your baked goods (bread, muffins, scones, etc...) as well as any dish of your choice!