Complex sentence: In September 2009, Russia invited Navantia to take part in the competition to supply Russian Navy with the new generation of amphibious assault ships to compete against the French "Mistral" class ships.
Split into simpler sentences: In September 2009, Russia invited Navantia to take part in the competition to supply Russian Navy with the new generation of amphibious assault ships. Once more it would be competing against the French "Mistral" class ships.