Mortise style lock set that secures door to the top, striker jambs and threshold. No markings or names .

Hi there, Robin. We appreciate you reaching out to us. We don't sell replacement handles for this type of door, unfortunately. Your best bet would be to contact the original manufacturer or a hardware retailer that specializes in french door repair parts. I am very sorry that we won't be able to assist with this repair but please let us know if you have any other hardware questions.