Hermès, the select handbag and scarf maker, accused luxury conglomerate LVMH of carrying out the "most important fraud in the history of the French stock market" in a court filing, as quoted in the Les Echos newspaper on Wednesday.
The two companies have been locked in a bitter feud ever since LVMH, which owns Louis Vuitton and dozens of other luxury brands, revealed that it had secretly built up a 17-percent stake in the family-dominated Hermès.
LVMH, led by tycoon Bernard Arnault, later built this holding up to 22.6 percent prompting Hermès to cry foul and accuse Arnault of surreptitiously trying to add Hermès to his large stable of brands.
In its accusation at a French business court, Hermès accuses LVMH of using highly complex financial instruments set up by top French banks that enabled it to conceal its buying spree from French regulators.
Hermès demands that LVMH sell back the stock to the three banks - Societe Generale, Natixis and Credit Agricole - which are themselves accused in court of acting as de-facto fronts for the alleged takeover attempt.
The courtroom battle is the latest in a barrage of legal proceedings launched by Hermès against LVMH, whose spokesman told Les Echos that the accusations by Hermès were unfounded and part of wider slander campaign.