Christian Louboutin introduced his signature red-soled shoes in 1992.
Louboutin began designing shoes under his own name in Paris, and the red sole became his defining visual feature during the early 1990s. According to the well-known origin story, he painted the sole of a prototype with red nail polish after feeling that the design needed a stronger finishing detail.
The red sole became a recognizable sign of Christian Louboutin footwear and later became the subject of trademark litigation in several jurisdictions. The color is associated with the brand, but the shoes themselves may use different upper materials and silhouettes.
The red sole should not be confused with a general red shoe. The signature refers specifically to the contrasting colored outsole used on many Louboutin designs.