Illustrator resorts to lawyers over long-running dispute about his sale of the comic-book franchise to Hachette Livre

He co-created the Asterix comic series about the adventures of the indomitable Gaul, but now Albert Uderzo is fighting his own real-life battle, and has filed a legal complaint against his daughter and son-in-law for "psychological violence".

The 86-year-old French illustrator told journalists at his house in Paris that "I have kept my mouth shut for years, but today I have decided to act. I want to turn the tables on those who are attacking me. Enough is enough."

Uderzo's daughter Sylvie and her husband Bernard de Choisy began a legal challenge in 2011 which claimed that her elderly father was being taken advantage of by those around him, who were exploiting his frailty, and influencing decisions about his literary estate.

The row dates back to 2007, when the duo were dismissed from their roles at French publisher Les Éditions Albert René, the company which had published the Asterix series. A year later, Albert sold his stake in the company which he owned with the daughter of the late René Goscinny, the writer with whom he collaborated on the comic book series, to the French publisher Hachette Livre. Uderzo and Goscinny co-created the series in 1959.

Sylvie claimed that by selling his share, her father had betrayed the spirit of the books, and opened the Asterix franchise to exploitation in the future. In a column in Le Monde in 2009, she wrote that it was "as if the gates of the Gaulish village had been thrown open to the Roman Empire".

However this week, Uderzo issued a statement that his daughter was "introducing and extending legal procedures that have no foundation." He rejected the claim that he was in a "state of fragility", and said that he is being harassed.

"The sole purpose of these acts is to undermine our psychological integrity and to hasten our debility, in order to get their hands on our legacy, which they covet," he said.

The first new Asterix book in eight years, Asterix and the Picts, was created by a new team, writer Jean-Yves Ferri and illustrator Didier Conrad and published by Hachette Livre. It was translated by Anthea Bell, who has been the series' English translator since 1969.

The 35 comic books in the Asterix series have sold more than 352m copies worldwide.