This was later restructured as a banking subsidiary, called the Société Française et Belge de Banque et d'Escompte (lit.

In the financial and economic crisis of the late 1880s, it ran into liquidity problems, which were resolved by an injection of cash from the Société Générale de Belgique.

[3]: 134 The Banque de l'Union Parisienne was founded on 5 January 1904, with initial capital of 40 million francs.

[2]: 2 Baron Ferdinand Baeyens, governor on the Société Générale, was administrator of the BUP from 1904 until his retirement in October 1913, when Jean Jadot assumed both positions.

It helped with the launch and expansion of Messageries Maritimes (shipping), Ericsson (telephones), De Dion-Bouton (cars), and so on.

The bank became closely involved with the industrial giant Schneider, helping financing in Russia, Morocco, and other countries.

[2]: 2 The bank invested in the Compagnie Française des Pétroles (now Total S.A.), holding about 13% of the capital, while Paribas held 19%.

Another major investment was with Citroën, which was having trouble finding investors due to its unorthodox management and poor profitability.

With governments failing to reimburse their bonds, and with companies with which it was involved going bankrupt, the bank's viability came into question as losses mounted in the 1930s.

The Banque de France was unwilling to see the BUP go out of business, and managed to assemble investors to recapitalize the bank.

The Société générale de Belgique withdrew its capital, but the BUP compensated by absorbing the Mirabaud bank.

As a consequence, the BUP owned the entire city block, which it remodeled between 1926 and 1932 with a new wing fronting the Boulevard, designed by architect Pierre Figarol.