Probably 1630s.
While an old gypsy crone tells his fortune, a naive youth is robbed by her accomplices, a subject popular among Caravaggesque painters throughout Europe in the 17th century. La Tour’s painting can be interpreted as a genre or theatrical scene, or as an allusion to the parable of the prodigal son. The inscription on the painting includes the name of the town where La Tour lived, Lunéville in Lorraine. (http://www.metmuseum.org/art/collection/search/436838)
It is believed that within his 30 years career La Tour produced about 40 paintings; some could have been painted by his son, Étienne. In fact, there have been problems with attribution to some of his paintings and many speculations that some could be forgeries. One of such paintings is The Fortune Teller, which portrays a 17th-century picaresque scene: a fortune teller and three sly thieves in the act of robbing a young man....
[https://artlark.org/2017/03/13/the-mystery-of-the-fortune-teller-by-georges-de-la-tour]