Which medieval code of laws was based on the legal norms of the Roman Empire?

It is likely that we are talking about the Justinian Code. It was indeed based on examples of Roman law, and this is not surprising, because after the fall of the Western Roman Empire, no more than a century had passed since this legislative body was published. Moreover, there was not some new code, it was actually a compilation of old laws. Although it should be noted that the special commission, which was created to form this set of laws, was allowed not only to systematize them, but also to make their own changes.