The Boy with the Star Tattoo by Talia Carner

From acclaimed author of The Third Daughter comes an epic historical novel of ingenuity and courage, of love and loss, spanning postwar France when Israeli agents roamed the countryside to rescue hidden Jewish orphans—to the 1969 daring escape of the Israeli boats of Cherbourg.
1942: As the Vichy government hunts for Jews across France, Claudette Pelletier, a young and talented seamstress and lover of romance novels, falls in love with a Jewish man who seeks shelter at the château where she works. Their whirlwind and desperate romance before he must flee leaves her pregnant and terrified.
When the Nazis invade the Free Zone shortly after the birth of her child, the disabled Claudette is forced to make a heartbreaking choice and escapes to Spain, leaving her baby in the care of his nursemaid. By the time Claudette is able to return years later, her son has disappeared. Unbeknown to his anguished mother, the boy has been rescued by a Youth Aliyah agent searching for Jewish orphans.
1968: When Israeli naval officer Daniel Yarden recruits Sharon Bloomenthal for a secret naval operation in Cherbourg, France, he can't imagine that he is the target of the agenda of the twenty-year-old grieving the recent loss of her fiancé in a drowned submarine. Sharon suspects that Danny's past in Youth Aliyah may reflect that of her mysterious late mother and she sets out to track her boss's extraordinary journey as an orphan in a quaint French village all the way to Israel.
As Danny focuses on the future of his people and on executing a daring, crucial operation under France's radar, he is unaware that the obsessed Sharon follows the breadcrumbs of clues across the country to find her answers. But she is wholly unprepared for the dilemma she must face upon solving the puzzle.