A descendant of the Hermès luxury handbag empire is engulfed in a public battle with the charitable foundation he founded after reports that he planned to cut its funding and instead adopt his 51-year-old former gardener and bequeath him billions. Nicolas Puech, 80, a secretive fifth-generation descendant of Thierry Hermès, who founded Hermès in 1837, has begun the legal process of formally adopting the unnamed former gardener and plans to leave him half of his €12bn (£10.3bn) fortune, according to Swiss media reports. Puech, who has no children, is attempting to cancel a “succession agreement” he agreed with a charity he established in 2011 to fund “the protection and promotion of public debate”. The Isocrates Foundation, which has a board of six including Puech as president, announced on Tuesday it has formally “opposed” its founder’s decision to cancel the inheritance contract. The foundation said it “isn’t in a position to judge the process or context” of the reports that Puech wished to adopt his former employee. “From a legal standpoint, the abrupt and unilateral annulment of a succession agreement appears void and unfounded,” the foundation said in a statement. “The foundation has opposed this move, while leaving the door open to discussion with its founder and president.” The foundation said it was established to fund and support “public interest journalism and media organisations committed to strengthening the field of investigative journalism” and civil society organisations “working towards responsible digitalisation and a healthy digital public space”. It said that as a Switzerland-based charity, it is “under the authority and surveillance of Swiss Federal supervisory board for foundations”. Puech, who is estranged from most of his family, recently began the legal process of formally adopting his unnamed former gardener and handyman, according to Swiss newspaper Tribune de Genève. The newspaper said the unnamed man of Moroccan origins is married with two children, and Puech refers to them as his “children” and “adopted son”. A lawyer for Puech did not respond to requests for comment. The lawyer told Bloomberg that his client may hold a press conference “to separate the fact from the fiction and to dispel some of the nonsense that has been reported in the media”. Puech is thought to own about 5.7% of Hermès’ shares. The stock market value of Hermès has soared amid a boom in demand for luxury goods since the pandemic. Hermès shares have almost quadrupled since spring 2020 giving it a €209bn market value, making Puech’s stake worth just under €12bn. Hermès declined to comment.