For the past week and a half, a continuous flow of traffic has slowly edged its way towards the bulky, yellow-hulled Corsican ferries berthed twice a day in Nice’s picturesque harbour.

Ordinarily, the final stage of a road journey to the foot of Mont Boron and the captivating sight of a sparkling Mediterranean is relatively straight forward, but this week, the volume of cars, camper vans and motorcycles has ensured a normally steady flow has slowed to a frustrating crawl, a situation exacerbated by soaring temperatures.

Corsica has grown used to welcoming large numbers of visitors, usually between mid-July and late August, but according to a report in Nice Matin, if traffic flow is any gauge, the Isle of Beauty’s population of 302,000 has increased by up to one third during the past week alone.

The surge in bodies and cars is easily explained – in Porto-Vecchio on Saturday, the Grand Depart will signal the start of the one hundredth Tour de France, a 212 kilometre opening stage hugging the island’s east coast.

This demanding opener is followed by two further Corsican-based legs of the world’s largest live sporting event which means that by the time the teams return to Nice for next Tuesday’s team time trial, the riders will have already completed 15% of the 3,360km contest.

Until this year, Corsica remained the only region of France not to have held a Tour stage. Despite repeated bids, the island was considered an unsuitable venue, a conclusion reinforced by logistical concerns and fears that it couldn’t accommodate the 22 teams, 198 riders and support staff numbering thousands.

Political tensions have also been responsible for scuppering previous bids, but one of the principle reasons for Corsica’s absence from the Tour’s schedules has been the absence of a suitable press centre.

The event’s worldwide popularity means a substantial 8,000sq m area is needed to accommodate sports journalists from all over the world. The problem has been solved with a novel arrangement – a ‘spare’ yellow-hulled Corsican ferry will host the press, mooring at Porto-Vecchio and following the race around the island each day, much to the delight of broadcasters expecting to transmit even more than the staggering 4,700 hours of race coverage they screened across the world twelve months ago. This year, 190 countries will be taking Tour de France broadcast feeds – sixty countries are taking the pictures live.

The Tour is one of sport’s biggest brands. The enormity of its television audience ensures it boasts the world’s largest viewing figures for an annual sports event and is rated third highest for any sporting event, behind only the Olympics and football’s World Cup, each held every four years.

By contrast to these two sporting and commercial colossi, the Tour de France offers sponsors an attractive opportunity for brand exposure both in France and internationally at a fraction of the cost of Olympic or World Cup sponsorship.

In effect, the 21-stage race, replete with almost 200 riders sporting shirts and shorts covered in logos, offers sponsors endless opportunities for marketable moments as it careers through mountain ranges, towns, countryside and past France’s most iconic monuments.

But wall-to-wall television coverage and a broadcast audience running to billions is backed up by a colossal, ready-made live roadside audience estimated to exceed 15 million.

It’s unlikely that 32-year-old Maurice Garin could have imagined how the Tour de France would change in the century following his 1903 success.

The Frenchman, known as “the Little Chimney Sweep,” became the Tour’s first-ever winner when the field consisted of just 60 riders (only 21 of whom were sponsored) who rode through the night in pursuit of a share of the total prize money of 20,000 francs.

Today, the Tour’s scale would astound Garin for the race has developed into more than a sporting spectacle to become a commercially-oriented event capable of attracting a staggering array of sponsors, partners, merchandisers and suppliers, each paying for the privilege of being associated with the Tour.

Yet one of the reasons for the race’s commercial appeal is its comparatively low cost. While it draws enormous broadcast and live audiences, the Tour’s past has tainted the brand. A succession of drug busts, tearful rider admissions and a lingering sense that not every team has jettisoned its reliance upon banned substances continues to hamper further commercial development.

The Amaury Sport Organization (ASO), the tour’s owner and official organiser, generates around 70% of its €110 million annual turnover from a variety of cycling events. The Tour de France is by far the largest, responsible for producing an estimated €62 million each year. Most of the money comes from the sale of television rights and advertising revenue invested into the event by almost 30 associated businesses that pay to have their logos beamed into the homes of over 1 billion people worldwide.

For sponsors, provided their team doesn’t fail a drugs test, this is undoubtedly money well spent. ASO claim that for every euro invested in the Tour, a sponsor is guaranteed a tenfold return. Such returns explain the number of T-shirts, hats and umbrellas sporting sponsor and official partner logos that add a striking, vivid colouring to each of the Tour’s 21 stages. Considering the Tour’s global reach, sponsorship in any capacity is an attractive proposition, although prospective commercial partners must adhere to certain rules.

“You can’t just come to us and say ‘I have a product, I want to sell that product’,” says Daniel Bal, the Tour’s deputy director. “If it works with our product, our logo and our colours, then we have a deal and we can work together.”

Not surprisingly, the most sought-after areas of sponsorship have remained within the control of France’s giants of cycling patronage for many years.

The multi-coloured jerseys, awarded to the king of the mountains, the best sprinter, the best newcomer and the overall Tour winner, have been coveted as valuable platforms for publicity-hungry organisations. The fabled maillot jeune, awarded to the race leader and, ultimately, to the eventual winner, has been sponsored by French bank Crédit Lyonnais since 1987. Though the bank teetered on the brink of bankruptcy in 1993 and was eventually acquired by Credit Agricole a decade later, it has continued to pay between $4.6 million and an estimated $5.5 million a year (under the guise of a renamed LCL Bank) to sponsor the yellow jersey. The bank’s latest deal, secured last year, will ensure LCL remain as sponsors until 2018 at least.

“This represents enormously good value,” says Jim Hardie, chief executive of Apex Sports Marketing.

“Considering the size of the race’s global audience, which will continue to grow provided the organisers can avoid any further drug-related scandals, there’s actually nothing better in world sport.

“It’s particularly attractive to a French company, however, as the whole nation is riveted to the race for three weeks every July, providing domestically-focused sponsors with what is incredibly cheap advertising.”

Unusually, the King of the Mountains jersey sponsorship has changed hands prior to this year’s race as Carrefour have been ousted by another supermarket chain, Champion, who are understood to be paying around $3 million a year for the privilege.

Of course, the folks sailing to Corsica for Saturday’s start have long appreciated that they’re attending an event boasting global status. Sponsors too privately acknowledge that the Tour’s cost of entry remains attractively depressed, but another scandal-free, celebratory year may persuade ASO it’s time to start raising its prices.