I have a carte de sejour , will I have to change it if I move address after the 29th March 19?
The Carte de Séjour obtained is no longer valid anyway and a new Carte de sejour would have to be applied for under non EU national terms – see question 3. Above
Not automatically. The new address would only need to be disclosed when the Carte is renewed per the conditions explained in the answer to question 3. above