Notice the top of the periscope on the top of the sliding canopy.
The instructor in the back seat has a poor forward view and so a periscope, is installed in front of him for better visibility.

The Fouga CM.170 Magister is a 1950s French two-seat jet trainer aircraft, developed and manufactured by aircraft company Fouga. Wikipedia
Top speed: 444 mph Range: 575 mi Weight: 4,740 lbs Length: 33′ Unit cost: $75,000
Engine type: Turbomeca Marboré First flight: July 23, 1952. It was used by many air forces in the world.