He studied law at Würzburg and Göttingen, became professor of public law in the university of Würzburg in 1799, and in 1819 was sent as a deputy to the Landtag of Bavaria. Having associated himself with the party of reform, he was regarded with suspicion by the Bavarian king Maximilian I and the court party, although favoured for a time by Maximilian's son, the future King Louis I.
In 1821 he was compelled to give up his professorship, but he continued to agitate for reform, and in 1831 the king refused to recognize his election to the Landtag. A speech delivered by Behr in 1832 was regarded as seditious, and he was arrested. In spite of his assertion of loyalty to the principle of monarchy he was detained in custody, and in 1836 was found guilty of seeking to injure the king. He then admitted his offence; but he was not released from prison until 1839, and the next nine years of his life were passed under police supervision at Passau and Regensburg.
Behr's chief writings are: