Olivier has illustrated "Under the Apple Tree in Bloom" ("Sous le pommier en fleur") by Henri Meunier, published by Grasset Jeunesse on September 24, 2025. This humorous and poetic picture book for ages 6+ follows a lonely forty-something whose life is transformed when he inherits an unexpected boarder – a hippopotamus from his adventurous uncle. Olivier's illustrations bring warmth and whimsy to this original story about friendship and letting go, creating visual poetry that complements Meunier's unconventional tale of an unlikely duo finding companionship.