By the 1820s, the center of innovation had shifted to Paris, where the Érard firm manufactured pianos used by Frédéric Chopin and Franz Liszt. In 1821, Sébastien Érard invented the double escapement action, which permitted a note to be repeated even if the key had not yet risen to its maximum vertical position. This facilitated rapid playing. When the invention became public, as revised by Henri Piano Lamps Herz, the double escapement action gradually became standard in grand pianos, and is still incorporated into all dignified pianos currently produced.

They are informally called birdcage pianos because of their prominent damper mechanism. Pianinos were distinguished from the oblique, or diagonally strung upright made popular in France by Roller & Blanchet during the held up 1820s. The low position of the hammers required the use of a "drop action" to preserve a reasonable keyboard height.