The steppe people defeated by Charlemagne's forces in the Avar Wars were the Avars. The conflict, fought mainly from 788 to 803, pitted the Frankish kingdom against the Avar Khaganate, a powerful polity centered in the Pannonian Basin of Central Europe.
Frankish expansion into Bavaria and northern Italy brought Charlemagne into direct contact with the Avars. In 791, Charlemagne led a major invasion along the Danube, while his son Pippin of Italy attacked from the southeast. Although disease among the horses forced Charlemagne to halt that campaign, Frankish pressure continued through raids, logistical preparations, and further invasions.
The decisive phase came in 795 and 796, when forces led by Eric of Friuli, Woynimir, and Pippin captured the Avar royal treasure known as the ring. Internal conflict had already weakened the khaganate, and its leaders submitted or lost effective control. The Franks seized large amounts of wealth and imposed their authority over the khaganate's western regions.
The Avars should not be confused with the Huns, Magyars, or Pechenegs. Those were different steppe peoples active in different periods and political settings.