When you search online for a profile of Slim Riahi, you find very little concrete information about the presidential candidate before Tunisia's revolution.

He was a newcomer in the National Constituent election of October 2011, spending a substantial amount of money on a lavish campaign.

However, at the time his Free Patriotic Union (UPL) only managed to gain a tiny percentage of the vote. In this year's elections the union has conducted an expensive, high profile campaign, and this time round it worked.

The UPL came third in last month's parliamentary elections and Riahi is expected to do well in the presidential vote on Sunday.

I catch up with him by one of the capital's tram stations. Before he buys a ticket and goes through the turnstiles he admits this is his first time ever on a tram.

I wonder whether he has ever taken public transport? He has certainly led a privileged life. Growing up with his family in exile in Libya, he went to university in Tripoli. He is secretive about how he made his fortune, and no one is really sure.

Some people say that it was down to his close connections with the Gaddafi family, and others suggest it is generated by his company’s successes in oil and construction. His rivals say he is only in Tunisia to amass more wealth, something Riahi vehemently denies.

He has promised to invest in the poorest regions of the country and create jobs. He tells me that he is "coming for change."

Riahi has been compared by some to Italy's former prime minister Silvio Berlusconi. He has a big stake in Tunisian media, and owns Club Africain, one of the most popular football teams in Tunisia, and currently top of the league.

There is no doubt that Riahi has used his money and the popularity of his football team to help his profile. Indeed, there is concern among some people that he is mixing his business interests with politics.

The election monitoring organisation I Watch says there is no evidence that Riahi has spent any more than some of the other leading candidates. However, Tunisia's recent history was dominated by an elite circle that dominated politics and business in the country.

Achref Aouadi, the dynamic, young president of the watchdog says that Tunisia has to be "vigilant" that this does not happen again.

Observing Riahi on his short trip on the metro, and a brief bus ride, I am struck by how important it is for him to show that despite his wealth, he understands the concerns of ordinary people.

However hard he tries to adapt his image, at the end of the day Riahi gets back into his chauffeured luxury Audi, surrounded by his bodyguards and entourage.

Despite the controversies surrounding his campaign, many say he represents a new kind of non-ideological politician in Tunisia.

His message will continue to appeal to many young Tunisians looking for a solution to the country's economic problems.

Whatever happens in Sunday's election, Riahi still has a role to play in the next government as a possible kingmaker. The16 seats in parliament of his party, the UPL, could be the deciding factor in a new coalition government.