After months of speculatoin and waiting, it has finally been confirmed. The Spring Festival will come to Disneyland Paris during April (and maybe more months):

"Swing into a Disney Spring, blooming with magic at Disneyland® Paris. Color and music blossom throughout Disneyland® Park. And with the smell of flowers and fun in the air, it’s sure to be magnifiScent”

Source: dlrpexpress