No. If there is no spousal gift (also known as a “gift to the last living”), the law provides that the surviving spouse may only claim one-quarter of the estate in full ownership when the deceased leaves children from another union (Art. 757 Civil Code).
Good to know: a spousal gift, drawn up before a notary, can increase the surviving spouse’s inheritance rights (Arts. 1091 and 1094-1 Civil Code).