I just visited it and became curious about this question. I guess a more answerable question might be - "Where were large iron ore mines in the late 19th century that France would've had access to?"
All the iron used for the Eiffel Tower was produced at the refineries of Fould & Dupont in Pompey, near Nancy in the Lorraine basin in North-Eastern France.
"Tous les fers de la Tour Eiffel, 24 types de cornières ouvertes et fermées, en tout 7,056,909 kilog., ont été fabriqués et livrés par M. Fould Dupont. Les ponts démontables Eiffel sont en aciers laminés de Pompey. "