Macarons
Pierre Hermé (Multiple locations) My personal favorite. The flavors are exotic and unique. They are better than Laduree (trust me). Pierre Hermé actually worked at Fauchon (anther competitor) and Ladurée before starting his own macaron shop.
Gelato
Grom (Multiple locations)
Bertillon (Saint-Louis en l’île)
Gelati d’Alberto (Latin Quarter)