The rouble's gains were limited even as oil prices climbed higher. It traded at around 63.5 to the dollar when oil prices last hovered near current levels in February 2020.
The rouble was up 0.3% against the dollar at 75.99 and had gained 0.5% to trade at 91.29 versus the euro.
The next year the brothers filed a complaint with a court in Vannes, not far from Yves Rocher's headquarters in France, seeking "real and fair justice".
The rouble would be under pressure from political risk in the run-up to the weekend, but could gain a foothold near 76 to the dollar, Sberbank CIB analysts said in a note.
"Any destabilisation of the political situation in the country is always a strong negative both for equities and for the rouble," said Alor Broker analyst Alexei Antonov.