The Capetian War was a three year conflict between Hugh Capet and his supporters, and Charles of the Carolingian dynasty. The war saw the death of Hugh and the return of Carolingian rule.
Charles, Duke of Lower Lorraine, had acted on behalf of the Holy Roman Emperor Otto II, and fought his fellow Francian nobles. He and Otto laid siege to Paris, but we're pushed back by a relief force commanded by Hugh Capet. This lead to Charles being considered a traitor in West Francia (as it was still known as) and thus unable to be elected ruler. So, when Charles' nephew Louis V died in 987, Hugh Capet was elected as King of the Franks.