Balthazar Napoleon de Bourbon, a jovial Indian lawyer and part-time farmer, has always been fascinated by France. Framed pictures of the Eiffel Tower and the palace of Versailles implausibly decorate his house in a dusty, bustling suburb of the central Indian city of Bhopal. He gave his children French names even though he has never set foot in France.

But he may soon make his first trip to Paris, after he was visited by a relative of Prince Philip, who told him that he is the first in line to the lost French throne.

This Indian father-of-three is being feted as the long-lost descendent of the Bourbon kings who ruled France from the 16th century to the French revolution. A distant cousin of Louis XVI and Marie Antoinette, he is alleged to be not only related to the current Bourbon king of Spain and the Bourbon descendants still in France, but to have more claim than any of them to the French crown.

The story of a potential Asian dauphin to one of the most important royal houses of Europe appears to be a poke in the eye for colonial history, and has sparked a rush of interest among royals in Europe.

Prince Michael of Greece, the cousin of Prince Philip, this week published a historical novel called Le Rajah de Bourbon, which traces the swashbuckling story of Mr Bourbon's first royal ancestor in India. Prince Michael believes Jean de Bourbon was a nephew of the first Bourbon French king, Henry IV. In the mid-16th century Jean embarked on an action-packed adventure across the world which saw him survive assassination attempts and kidnap by pirates to be sold at an Egyptian slave market and serve in the Ethiopian army.

In 1560, he turned up at the court of the Mogul emperor Akbar. It was the beginning of a long line of Bourbons in India, who centuries later would serve as the administrators of Bhopal and become the second most important family in the region.

Michael of Greece, who lives in Paris and is of Bourbon descent, believes his detective work on his newfound Indian "cousins" is more than just the latest whimsy in a history of attempts to uncover relatives of Louis XVI and Marie Antoinette.

"If I am right - and I don't have absolute proof, but I completely believe in my theory - then Balthazar Bourbon would be the eldest in the line," he told the Guardian.

"This is the cherry on the cake. Mr Bourbon is head of a decent, dignified, middle-class Indian family. They look so Indian and yet bear this name. When you look at them, it seems incredible. The more unbelievable it is, the more I believe in it."

He said several of his royal relatives in Spain and France were "quite excited and thrilled to have found a new branch". He was in favour of a DNA test, perhaps from a surviving lock of Bourbon hair, to establish the facts.

From his home in the Bhopal suburbs, Mr Bourbon, 48, said he would be glad to take a DNA test, but remained stoical about the "hypothetical question" of whether he was heir to the throne. Conscious of the bloody outcome for royals in France, he felt royal status could bring "trouble", not to mention questions from skeptical historians.

Still, he has long had a brass plaque above his front door reading "House of Bourbon" with the fleur-de-lis crest of the French monarchy. His wife runs the neighbouring school for local children, called the Bourbon school. The family is Catholic and keeps Bourbon relics, including a sword, in their home. He said he felt "a sense of pride" when contemplating the picture of Versailles on his wall.

But he is aware that his family's fortunes waned in Bhopal long ago. He describes the Indian branch of the family as Bourbons on the rocks.

"From the day I was born, I was made to understand that I belonged to the family of the Bourbons," he said.

"I may be from a royal family but I live my life as a commoner. I didn't have time to learn French as a teenager because my father's death meant I had to work to look after my mother and sisters. Life has been very tough for me."

When his sister went to France on holiday she visited a castle once owned by Bourbon kings. It was closed to the public but she showed her Indian passport with the Bourbon name and was allowed in.

"I don't know if any of this will change my life," Mr Bourbon said. "The fact is, we've been having visitors from England, France and across Europe for years, curious about our family name.

"All these travellers, all this publicity, but nothing has happened yet. So how can I believe that something will change now?"

Backstory

War, assassinations, child kings, opulence and revolution marked the two centuries during which the Bourbons ruled France. They were known as much for their colourful personal lives as their politics. The first king, Henri IV, came to power in 1589 and was reputed to have more than 60 mistresses and 11 illegitimate children. Later Louis XIV, the Sun King, became the most powerful ruler in French history and one of the longest reigning kings in Europe. In 1793, Louis XVI was guillotined by revolutionaries, followed months later by his wife Marie Antoinette. Different branches of the Bourbons were restored to the throne from 1814 until the revolution of 1848.