Does the Laffer curve exist?

Yes, the laffer curve was used to put forward the argument that incessant increase in tax rates is not productive. In the US, the Laffer curve was used for implementing tax cuts in the 1980s. You can read about the Taxation System in India – Types, GST, VAT, Objectives, Limitation, Laffer Curve in the given link.

The Laffer Curve was developed by an economist named Arthur Laffer.

Further readings:

1. Global Minimum Corporate Tax – Minimum tax rate proposed by the G7
2. Base Erosion and Profit Sharing