The article expresses the research results on an ancient map numbered Ge A-395 without title, legend, inscription and date being preserved in the National Library of France. Based on the drawings in the map and the comparison of reliable documentary sources (script and maps) with the same date, the author concludes that Ge A-395 is the map of Hanoi and its date can be within the late 1876 and before 15 May 1883. The author's opinion was accepted by the National Library of France, and the date of the map Ge A-395 on the card of general list BnF was corrected from [17..] (18th century) to [1876-1883].