Yes, France and England definitely were aware of them. The Viking Age is traditionally considered to begin with the raid on Lindisfarne Abbey (England) in 793.

Furthermore, the defining transition between the Early Middle Ages and the High Middle Ages in Western Europe is the spread of the Normans. While this is often dated specifically to 1066, when a succession war occurred in England between the native Anglo-Saxons nobility the Norwegian crown, and the Norman ducal house (the king of Denmark also had a claim to the throne as a successor to Cnut and unsuccessfully invaded a few years later), this is an Anglocentric date. The Normans, descendants of Norsemen who settled in France, expanded out from Normandy around this time not just in conquest of England. For example, the leaders of the First Crusade, a few years later, were mostly Normans who ended up with territory in Italy. 1066 is, however, fairly accurate as a marker for the end of the Viking Age, specifically, because that is more territorially limited than the High Middle Ages and the Norman and Norwegian invasions of England during the succession war were the last significant viking expeditions.

In between, there was plenty of Norse-English and Norse-French interaction. In addition to attacking France enough that they permanently occupied territory in northern France (Normandy), a region of northern England, the Danelaw, was controlled by Norse rulers. Furthermore, around 1000, the Danish royal family, the Knytling dynasty, took over England, most notably under kings Sweyn and Cnut.