Its called Olfactory Marketing and started back in the 1980s when British supermarkets discovered that if they had a bakery in a supermarket that blew the smell of fresh baking bread back into the store, not only did they sell more bread, they also sold more food as a whole.

French car maker, Citroën, is now set to follow the bakers with the launch of the Citroën C4 in Australia in March, offering as standard a scent-diffuser in the ventilation system and a range of nine different scents.

The success of Olfactory Marketing and Citroën's decision to make it a feature of he C4 is based on the fact that smells can have a significant effect on mood and sense of well being and their effect is usually very subtle. As well as providing a very pleasant environment for users of the C4, the perfumes also have ability to inspire an environment that is conducive to safe driving.

Until Citroën's innovation, the smells normally associated with cars were limited to that elusive 'new car smell', the aroma of leather and the blend of smells associated with a well used second hand car!

"The sense of smell has, at best, been ignored and more frequently negated by car makers," says Oliver Lehmann, the marketing project leader for the C4 Perfume diffuser programme. "The usual idea is to prevent any odours coming through the interior and yet sales of car air fresheners are booming. We were determined to address this paradox in the Citroën C4 and to do it with superior quality and a price that made it a creditable alternative to conventional after-market air-fresheners."

Citroën test marketed the idea of perfume diffuser kit with a special edition Citroën C3 in 2003, the C3 Buddha Bar, which offered five different fragrances based on the theme of Feng Shui. Not only did the demand for this special edition exceed all expectations, it was clear that the main attraction of the C3 Buddha Bar was its perfume pack, which became an aftermarket accessory for the Citroën range.

"It was immediately clear that the perfume diffuser was a product that was out of the ordinary, with strong innovative potential," explains Oliver Lehmann. "Working on a ten month time frame, we had to go where Citroën had never been before, to developed a perfume diffuser and establish our credibility in the design and development of automotive perfumes."

But while Citroën designed and developed the distribution process for the perfume, it called in experts to design the smells themselves.

"A product of this type is always complex," says Gregory Magert, Managing Director of Parfum d'image, the company tasked with finding the right smells for the Citroën C4. "The composition of each perfume uses between 20 and 50 raw materials and its production requires input from dozens of suppliers around the world."

Citroën contacted Parfum d'image in late 2002, having already designed the diffuser system. Their job was to come back with fragrances that reflected the image of Citroën, which would appeal to customers and which would provide a beneficial driving environment.

"We developed nine fragrances that are in our terms very high specification, but which are also easily and quickly accessible in the driving environment of the Citroën C4," says Mr Magert. "These fragrances represent pleasure and well being. With the fragrances developed, we then worked with Citroën on the practical aspect of ensuring even and quick diffusion within the C4. Finally we worked on the packaging of not just the fragrances that are delivered with the new car, but also the refills available from Citroën dealers."

In total there are nine different fragrances available for the new Citroën C4, split into three groups:

• Vitality: mint and musk; jasmine and mimosa; citrus and passion.
• Travel: vanilla; cinnamon and ginger; amber and sandalwood.
• Well-being: lotus flower; soft lavender; ylang and bamboo.

But it was not just Citroën that had to develop new systems and processes for its entry into the perfume and fragrance market. Its dealers are also being trained!

Each new Citroën C4 is delivered with a kit of three refills, one from each group, which is enough to last for around six months of normal use. At the six-month anniversary of the purchase of the Citroën C4, owners will be invited to, via a letter, scented with a fragrance, Cinnamon and Ginger, not issued with the C4, to return to their Citroën dealer for refills. Here they will find a special display counter holding 108 scent cartridges, brochures and scratch and sniff tabs that will allow C4 owners to take samples home before buying refills.

"Citroën's decision to launch the perfume diffuser with the C4 was a strategic decision that we knew would provide customer benefits and being customers to our dealerships," says Oliver Lehmann. "Now that the C4 is on sale it is clear that this innovative programme is, indeed, introducing new customers to Citroën as well as bringing them to our dealers' parts departments. The programme clearly has the sweet smell of success!"