To achieve this objective, the engineers:

• simplified a number of parts and mechanisms to the extreme,

• grouped several functions in a single part,

• removed all parts that are non-essential to the running of the car or to the comfort and well-being of its occupants.

The dashboard has gone, and its usual functions are now grouped on the central console and the fixed hub of the steering wheel. The central console thus includes the active loudspeakers, gearbox controls and tactile screen giving access to the onboard computer, navigation system and air conditioning controls. The controls for the indicators, lights, wipers, horn and cruise control/speed limiter are on the fixed hub of the steering wheel, as are the tachometer and lights for the indicators, headlamps and warning signals.

Another example of simplification: the part used for the front bumper, which includes the headlamps and chevrons is the same as the part making up the lower part of the tailgate at the rear. This contributes to the assertive design of C-Cactus while bringing economies of scale in production.

This simplicity is also reflected in the design of the front end, which comprises just two parts: a fixed bonnet comprising the front wings, and a flap giving access to the vehicle maintenance functions (oil, windscreen washer, etc.).

Reflecting a similar approach, using the air conditioning makes it virtually unnecessary to open the windows. A simple sliding mechanism is therefore provided, since this is sufficient in normal use. Engineers were thus able to get rid of both the window frames and the opening mechanism.

At the same time, a number of monoblock units are used for C-Cactus to reduce the overall number of parts.

The door panels, for example, are made of two parts, compared with twelve in a conventional hatchback.

The seats also comprise two parts: a highly comfortable, moulded, coloured, integral-skin foam part for the seat, and a solid monoblock frame to hold the foam in place and fix the seat to the floor rails. The ergonomics are excellent and – here again – the number of components is limited.

Advanced ecological features

To achieve real environmental impact, Citroën's objective has always been to market technologies and vehicles that are affordable to the greatest number. The objective with C-Cactus is to go one step further, by bringing out a car whose hybrid HDi drivetrain makes it truly ecological car, but that can be sold at the same price as an entry-level family car.

With its diesel hybrid drivetrain combining a 70 bhp DIN HDi diesel engine with a particulate filter and an electric motor providing additional power of 30 bhp DIN, C?Cactus consumes just 2.9  l/100 km with CO₂ emission levels of 78 g/km over a combined cycle.  In urban use, ZEV (Zero Emission Vehicle) mode provides silent, all-electric operation. On journeys involving successive acceleration and deceleration, the hybrid system limits fuel consumption by using both types of energy.
Other points also help to make C-Cactus a car that respects the environment.
The solutions adopted for the design of C-Cactus also contribute to bringing down fuel consumption and CO₂ emissions. Using fewer parts makes the vehicle 15% lighter than a C4 Hybride HDi for a total weight of 1,109 kg.
The tyre width has also been kept down (205/45 R21) on C-Cactus, which adds to  environmental performance.
Fewer parts also means smaller quantities of raw materials. In additon, a significant part of the materials used are recycled or recyclable. The windscreen and windows, for example, are made of recyclable glass. The tyres are also recyclable, as is the crude steel used for the door panels. This metal is unpainted and unvarnished but has been treated for corrosion.
The protective mats are made of recycled leather, taken from leather cut-offs that cannot be used by conventional tanneries. Many parts are made of cork, a natural material made from the bark of oak trees. The felt used for the door panels and fascia stowage compartments is made from wool. This material uses no chemical additives and is both recyclable and biodegradable.
The top speed of C-Cactus has deliberately been capped at 150 kph. This choice not only contributes to the car's good environmental performance, it also reflects Citroën's efforts to develop a green vehicle illustrating a new approach to the car, in which the motorist is in harmony with his/her surrounding environment.

Looking for simplicity: intelligent, fun exterior design

C-Cactus has a unique personality: appealing, modern and offbeat, with its simple shapes and mix of round, curving lines. The original styling also reflects ingenious design choices. Throughout the design process, the focus was very much on simplicity. This led to the development of ingenious solutions that contribute to the attractive offbeat design of C-Cactus.
At the front, the headlamps of C-Cactus give the vehicle an appealing air with their rounded and slightly angular forms. They are underlined by two cylindrical air intakes cut out of the bumper, above an air intake grille of modern design which, while contributing to the vehicle's rounded forms, also adds a muscular energetic touch. The raised bonnet and two air intakes also contribute to the dynamic looks of C?Cactus.
The vehicle's rounded forms are reflected in its profile. The dynamic design lines are accentuated by the forward flowing roof line and the asymmetric doors made of crude steel that has been treated for corrosion.
The doors feature an original cut-out since the fixed windows remove a number of the constraints that usually apply to design.  Shaped to provide easy access to the interior, they give C-Cactus a curving, sleekly muscled appearance. The use of crude steel treated for corrosion, but without paint or varnish, contributes to savings in production costs while giving a strong, contemporary look.
The high waistline and 21-inch wheels also underline the strong character of C?Cactus.
The wheels were the focus of particular attention. Large-diameter wheels and low-profile tyres have become key styling features in vehicles of strong, contemporary design.
Citroën worked with Michelin on the development of low-profile tyres with a large diameter and limited width. The low ground friction area limits fuel consumption and, at the same time, tyre production costs are kept under control since the manufacturing process requires only a small amount of rubber.
For new and even more original styling, these specially designed tyres feature a green pattern on a white background printed inside a wide groove spanning the entire tread.
The same styling codes can be seen at the rear, where a combination of curves and taut lines illustrate the car's dynamic and appealing personality. The chevrons identify this car as a Citroën. The name "Cactus" appears in relief on the bottom of the tailgate, in a young, smooth, modern printface.
The rear lights, which resemble the headlamps in shape, boast an innovative feature: cut-outs in the interior plastic that let the driver see through. This innovation considerably increases the driver's field of vision and may be particularly useful in manoeuvres, for example.

Fewer features for greater impact: a welcoming, attractive and cleverly designed interior 

C-Cactus is also an original and ingenious car on the inside. The design cut-outs, choice of materials, patterns and colours give the cabin a minimalist, attractive and airy look.
The cabin materials reflect innovative choices. Their quality is immediately visible. Looking beyond their appearance, they are also economical and ecological. For example, cork is used for many decorative parts, as well as for the air vents and air conditioning panel. The floor features a pattern in recycled leather. The white lacquer finish of some parts and the visual effects created by the materials used contribute to the original design and perceived quality of the cabin.
Another key idea was to enhance the offbeat styling of C-Cactus by reducing the number of parts and the quantity of materials used for the decor.
Non-essential parts, such as the dashboard, are absent, while some of the parts that are usually hidden have been included in the decor. This is the case, for example, of the steering column, air conditioning ducts and the grid for fore-and-aft adjustment of the front seats. These features add a modern and original touch to the cabin. The refill for the scented air freshener is also visible. It contributes to the attractive appearance of the cabin, while enabling the driver to see how much is left.
The decor has not been put in. It has been created by removing material. This idea of decorating "in a vacuum" is reflected in the patterns present on the door panels and seat frames. The patterns cut-out in the door panels show the apple green felt inserted between panel and metal. The main role of this part is to soundproof the vehicle, but its colour and cut-outs make it an integral part of the décor.
The same flower, plant and butterfly patterns – symbolising the environment, purity and well-being – are also found on several other cabin features. They are cut out, for example, in the white lacquer seat frame. These cut-outs show the coloured foam used for the seat cushions and give it a decorative quality.

Pertinent choices for an easy and enjoyable ride

C-Cactus boasts advanced equipment, optimised on-board space and modular design at an affordable price. Passengers have all the comfort essential to their well-being.
First, the ignition key of C-Cactus is a portable MP3 player with a touch screen. When it is plugged into the fixed hub of the steering wheel, it is recognised by the vehicle which can then be started.
The fixed-hub steering wheel includes a wide variety of functions. In addition to the usual controls, it also includes the speedometer, which is of an unusual design. The figures, placed in relief around the hub, rotate according to speed and are positioned with respect to a fixed point.
A second touch screen on the central console includes a navigation system to guide the driver on the road. It also serves as an onboard computer. This equipment endows C-Cactus with high-tech advanced features while also keeping costs down, since functions are grouped together.
The central console features two powerful high-quality active loudspeakers that provide C-Cactus with an excellent sound system. Their ingenious layout limits both wiring and installation costs.
Generous interior space ensures passenger comfort. C-Cactus boasts the dimensions of a family car (4.2 metres long and 1.8 metres wide) with a generous and modular boot (between 500 and 1,100 litres).
The rear seat, placed on a rail, slides up against the front seats.  The floor pan, which is integral with the rear bench, also slides forward to reveal a subfloor. This reveals a virtually flat surface area to load bulky objects.