The building has a layered afterlife. From 1896 until 1913 it served as Franca's public jail and courthouse, a functional structure of brick and stone where the city's criminal business was conducted. In 1913, the judicial apparatus moved out and the City Hall moved in, renaming the building the Paço Municipal Rui Barbosa. Later it would house the municipal council chambers. Finally, in 1970, after serving so many civic purposes that its original identity had become almost incidental, it settled into its most lasting role: a museum. On August 11, 1997, Condephaat — São Paulo state's historical heritage council — formally declared the building a protected heritage site through Decree 7,420. Victor Dubugras, the French architect who designed it, would become known as one of the foundational figures of architecture in São Paulo, responsible for train stations and civic buildings across the interior.

The collection runs to approximately 4,000 objects. Documents. Manuscripts. Photographs. Furniture. Weapons. Clothing. The range of material reflects the museum's mandate, which is not to document one story but to preserve the whole sedimentary record of a region the nineteenth century called Sertão do Capim Mimoso — the backcountry of tender grass — a territory that once stretched between the Pardo and Sapucaí rivers along the old Caminho de Goiás, the colonial road toward the gold mines. This corridor cut through what is now northwestern São Paulo state and the southwestern edge of Minas Gerais. Franca was its commercial center. The museum's holdings therefore include objects from cattle drives and coffee fazendas, from immigrant households and town halls, from the settlers who cleared land and the families who stayed when the gold gave out and the cattle gave way to shoe factories.

One treasure sits in the library. The José Chiachiri Museum keeps the complete print run of every newspaper that circulated in Franca from 1881 through 1995 — more than a century of the city talking to itself. Birth announcements. Obituaries. Political scandals. Ads for lost cattle. Editorials about which rail lines should come through and which should not. The newspaper collection is, in a sense, the most democratic part of the archive: every voice that could afford a subscription made it into those pages, and the bound volumes now preserve a civic biography no single memoir could match. Beside them, 2,000 book titles on regional history, 576 periodical volumes, and 894 manuscript copies fill out the specialized library. Researchers from São Paulo State University's Franca campus use the collection regularly, producing dissertations and monographs that feed back into the city's understanding of itself.

In the interior of São Paulo state, where summer humidity can reach levels that destroy paper, the museum holds a functional distinction: it operates the only climate-controlled archive in the region. That seems like a footnote until you consider what preservation actually requires. Mold spreads in wet air. Ink bleeds. Leather cracks. Photographs separate from their mounts. An air-conditioned archive is, in tropical Brazil, the difference between documents that survive another century and documents that dissolve within a decade. The museum welcomes around 100 visitors per day, hosts traveling exhibitions, loans pieces to partner institutions, runs educational programs for schoolchildren, and organizes debate cycles and book launches. Its archive accepts researchers. Its library opens to the public. For a city of 350,000 people in the agricultural interior, the scale of cultural infrastructure is unusual.

Seventy years after José Chiachiri pitched the idea, the museum he founded has consolidated itself as one of the most important historical institutions in the interior of São Paulo. Its collection is a reference point for anyone studying the settlement history of northwestern São Paulo. The building itself — Dubugras's eclectic public jail — is now a heritage site. The newspaper collection is an anchor for regional journalism research. The model Chiachiri proposed in 1957 — find a building, collect the past, staff it modestly, open it to the public — has become a template that other mid-sized Brazilian cities still study and imitate. The journalist who had the idea did not live to see any of this. The institution he founded now carries his name on the façade, exactly where his byline used to sit on the newspapers he wrote for.