Let's start with FJL's parents' marriage:

Francisco Alejandro LOUBET
Spouse: Teresa MACHADO
Marriage: 18 May 1885
Mazatlan, Sinaloa, Mexico

Father's birth:
Francisco Alejandro LOUBET
Birth: 6 Mar 1858
Mazatlan, Sinaloa, Mexico
Parents:
Father: Francisco LOUBET
Mother: Juana GUZMAN

Outside of Sinaloa, another place to think of looking would be Morelia:
Jose Teodoro Francisco LOUBET MARTINES
Sex: M

Event(s):
Christening: 02 Apr 1833
Sagrario Metropolitano, Morelia, Michoacan, Mexico

Parents:
Father: Juan LOUBET
Mother: Magdalena MARTINES

And ultimately I suspect you'll be looking in Aude, France.

Going in the other direction, in 1896 the company Loubet y Compania changed its name to Fundicion de Sinaloa. Alejandro Loubet was the administrator of the company until 1900, when he was replaced with the Frenchman Raul Bigot.

In that year, 1900, the mining company Compania Exploradora de Minas SA was formed to exploit mines in Sinaloa, Durango, Chihuahua, Sonora, Nayarit and Baja California, with a capital of 10 thousand pesos. Of the 10 thousand shares, Alejandro Loubet received 250 (as did General [and governor(!)] Francisco Canedo, who was to die 9 years later).

Separately, in 1905, Express Maritimo de Mazatlan SA was formed with a capital of 12 thousand pesos; of the 120 shares issued, 5 went to Alejandro Loubet.

I could go on and on. Loubet was quite a guy. Alejandro bought German mining equipment from my grandfather, Pedro Inzunza McKay, his contemporary.