(Modifying and completing this earlier answer.)

Barbarians of the Late Roman Empire, and Franks in particular, were coalition of various if often related, people having lived along the limes sinces decades, and for most of the Rhineland leagues, since the turn of the millenium; being pretty much "peoples of the border" to quote Guy Halsall, in that they had a strong history of relations with Romans : trading, warring, being employed as seasonal workers, migrating in Romania (either as refugees or deportees) and especially since the IIIrd, finding military employment in the Roman Army.

As such, Frankish peoples could already be found in Gaul in the IVth century, where many of their officers and leaders obtained prestigious and powerful functions as generalissimos or consuls. They didn't form a single entity yet, and were made-up of small entities whose statute was defined by their negotiated relation with Romans : the most famous of them are called Salians and Ripuarians, probably in relation to their law and statue as Roman federates and "border-guards", similarily, other groups were settling in northern Gaul in the IVth to Vth centuries, e.g. Brittons and Saxons on the western coast, Alans along the Loire (originally as garrisons), Alamans along the Rhine, etc.

Being in permanent contact, or even settled among, with Romans; these Barbarians increasingly adopted Roman social codes altough maintaining their specific identity which was as much about their cultural particularities than their specific political and institutional role : the second could even be considered more relevant to their social history, as being Barbarian wasn't much about language or faith, than obeying a Barbarian petty-king and adopting the codes he followed which in the IVth to Vth century meant mostly romanized codes with a Barbarian coloration. Thus, "fiscal refugees", military deserters, slaves, your usual destitute people etc. from Roman Gaul gradually made up a good part of the Frankish peoples, which was something most of late ancient Barbarians went trough.

At the difference of the relatively swift establishment of quasi-independent realms by Barbarians in most of western Rome (Goths in Italy and Spain; Burgundians in Gaul; Vandals in Africa, etc.), thus hijacking Roman public service, administrations and overall institutions at their service, Northern Gaul in the late Vth century was in a relatively poor state, somewhat comparable, if more limited both in scope, to what happen in the same time in post-imperial Britain.

Indeed, since the 430's/450's, imperial authority had virtually disappeared north of the Loire, leaving only a series of officers turning warlords (who, even when Roman as Syagrius, most probably based their military power on Barbarian units) in the same time the Roman public servants and bureaucrats (militia), not being payed anymore turned to alternative situations which involved self-appointed mandate mixing civilian, military and even religious responsabilities sometimes (a trend which was arguably already growing in the Late Roman Empire) and even that had a relatively limited success in most damaged regions, with episcopalian network significantly declining in northernmost and easternmost parts of Gaul.

And indeed, aristocratic graves displaying weapons, "ethnic" jewels, deposit of beer, presence of runes, etc. would hint at Frankish aristocracy stressing its Germanity over Romans, relegated in the background.

But a closer look gives seemingly contradicting informations : weapons are the same than used by Romans, jewels were made in Eastern Roman workshops out of Indian precious stones, beer deposits were completed with wine deposits, runes are relatively rare and fairly short (such as spelling ALE). This kind of aristocratic grave was, critically, unknown in Germania proper at the same time : what we'd have there would be actually mixed displays of "Barbarity" and "Romanity", from peoples that were part of both worlds and wanted to make sure trough funeral display that people were aware of it.

Eventually, we can't really say if the people being buried there were Frankish warrior-aristocrats having adopted Roman cultural features or if they were Romans having adopted Frankish social codes or, likely, both assuming the difference was even relevant.