Very informative video on the Merovingians by Ryan M. Reeves (PhD Cambridge), Assistant Professor of Historical Theology at Gordon-Conwell Theological Seminary.
15:00 - The Carolingians were originally known as "Mayors of the Palace" (like a chief of staff position) in the Merovingian dynasty who usurped the throne after a period of turmoil due to sibling rivalries and the destructive scheming of one of the wives Brumhilde (think Killary of the Early Middle Ages).
An early Carolingian king Charles Martel was the first of the "Franks" to establish an alliance with the Papacy and deposed the last Merovingian king Childeric III with the Pope's help.
His grandson was Charlemagne, the 1st Holy Roman Emperor. There is a direct bloodline from the Carolingian kings to the Capetian dynasty (St. Louis, Louis XVI, etc) to the Bourbons.
They are NOT descended from the Merovingians.