Citroen has already made waves with the launch of its unusual C4 Cactus hatchback, and it has gone one further at this year’s Paris Motor Show by unveiling a superfrugal air-powered version.

The C4 Cactus Airflow 2L is based on the standard car but showcases some clever new technology to dramatically improve its fuel consumption.

Ditching the already-frugal 1.6-litre diesel unit for a 1.2-litre turbocharged petrol, the key to the HybridAir system is a network of hydraulic pipes and tanks which hold nitrogen, air and oil.

The Airflow can release pressure in the tank to drive a hydraulic pump which drives the wheels

Just like a conventional petrol-electric hybrid uses battery power to supplement the combustion engine, the Cactus Airflow can release the pressure in the tank to drive a hydraulic pump which drives the wheels.

When coasting or light braking the car’s kinetic energy can be used to drive the pump in the opposite way and recharge the tank.

Added to this, the Airflow 2L uses a redesigned exterior to dramatically improve its aerodynamics, including 19-inch alloy wheels and aluminium, plastic and carbon fibre to save weight.

The net result of this is that Citroen claims 141mpg – the equivalent of the 2L/100km target set by the French government.

Production has not been confirmed, but the C4 Cactus Airflow 2L could offer an alternative to conventional electric hybrids at a lower cost.