What were the names of Gustave Eiffel's grandparents?

Answer 1

The surname of Gustave Eiffel's paternal grandparents was Bönickhausen. (I don't know their first names). Gustave was born in Dijon, France, but his father's ancestors came originally from the Eifel mountains district of Germany. Gustave was the first legally to change his surname (in 1880) to Eiffel -- the name that his family had customarily used in France since their move to Paris at the beginning of the 18th century.