france was forced to open the ports of saint-nazaire and lorient to the kriegsmarine and to cede the french congo , alsace-lorraine and french flanders ( nord-pas de calais , the department of nord , and roughly the arrondissements of lille , douai and dunkirk ) with future territorial adjustments to follow in northern and eastern france , while germany agreed to gradually withdraw from the occupation zone and relinquish authority back to the vichy government .