[3] Brongniart had spontaneously submitted his project, which was a rectangular neoclassical Roman temple with a giant Corinthian colonnade enclosing a vaulted and arcaded central chamber.

"[3] From the second half of the 19th century, official stock markets in Paris were operated by the Compagnie des agents de change, directed by the elected members of a stockbrokers' syndical council.

Officially, the agents de change could not trade for their own account nor even be a counterpart to someone who wanted to buy or sell securities with their aid; they were strictly brokers, that is, intermediaries.

This was known generically as CATS (Computer Assisted Trading System), but the Paris version was called CAC (Cotation Assistée en Continu).

The Palais Brongniart hosted the French financial derivatives exchanges MATIF and MONEP, until they were fully automated in 1998.

The site was open to ticketed members of the public and included food, shops, and multiple areas to watch the games.