You're referring to the Dassault Aviation DASS-127 English, also known as the Dassault École de Pilotage or simply "English"!

Are there any specific aspects you'd like to know more about?

The DASS-127 English was designed as a two-seat jet trainer, with a focus on simplicity, reliability, and ease of maintenance. The aircraft features a sleek, single-engine design with a T-tail configuration.