Alliance Rostec Auto - of which Renault owns 61.1 percent in partnership with Russia's Rostec - raised its stake in Avtovaz to 83.5 percent from 64.6 percent in May, taking its holding above the 75 percent level where Russian law requires a mandatory tender offer to be launched for minority shareholders.

Renault said its offer would run to Sept 10 and be priced at 12.40 rouble/share for common shares and 12.20 rouble for preferential shares.

(Reporting by Gilles Guillaume; Writing by Geert De Clercq; Editing by Mark Potter)