Francesca Eastwood -- DEATH THREATS After Destroying Birkin Bag

Clint Eastwood's daughter has been bombarded with vicious online death threats after she publicly demolished a $100,000 Birkin bag in the name of art, TMZ has learned.

Francesca Eastwood, star of "Mrs. Eastwood and Company," and her BF Tyler Shields took a chain saw to the pricey bag and then LIT IT ON FIRE ... which has angered dozens of fashionistas (and many who are just economically challenged).

Eastwood has been receiving death threats via Twitter and Facebook, such as:

-- "Some of us actually have to work and live check 2 check, spoiled rotten bitch to burn 100k bag."
-- "You’re a stupid whore. How f***ing dumb can you be."
-- "You should kill urself, ungrateful bitch – wasted money when families can't eat."

Sources close to Francesca tell us ... the 19-year-old said she knew people would be shocked, but never expected this level of hatred. We're told she's been telling friends ... people just don't understand art.