[1] He pushed for the reconstruction of a fort located in the north of Saint Louis,[1] [2] work for which he commissioned Rodríguez Miró, governor of Louisiana.

In addition, Perez had to face Osage tribes, who were attacking the European settlements of the province.

Perez also helped trader Louis Lorimier promote the migration of members of the Shawnee and Lenape tribes, natives of eastern Mississippi, to Ste.

He also asked the New Orleans government to establish several fortifications at the mouths of the Des Moines and Saint Peters Rivers in order to keep the British away from the Amerindians, whom they were influencing, but the government rejected the proposal because, according to him, the forts would be too far from Saint Louis, and instead would be near areas with little or no French-Spanish presence.

However, although Perez himself welcomed them when they reached St. Louis in 1789, and provided them with various goods (provisions and horses) and guides, the American settlers were only living there for a while, as they then returned to their country.