Wales' Jones won four bouts in Hamburg to reach the final only for Canadian opponent Ivett Gonda to withdraw.
The London 2012 gold medalist missed March's Dutch Open and April's Presidents Cup with her injury.
The 22-year-old used the German event to improve her fitness ahead of the European Taekwondo Championships in Switzerland later this month.
Jones beat Jennifer Richter of Germany 21-3 in her first match of the day, and Genesis Anduja of the Dominican Republic 14-2 in the second round.
The European Games champion progressed with a 14-2 quarter-final victory over Germany's Rhonda Nat, then beat Belgian's Raheleh Asemani by the same score.
Britain's Feyi Pearce, 19, won a bronze medal in the -58kg category, losing 8-7 to Germany's Amir Mohammad Hosseini in the semi-finals.
Josh Calland, 17, beat fellow Briton Archie Waldock on the way to the quarter-finals of the -58kg division, before losing to South Korea's Kim Tae-Hun.
Olympic taekwondo champion Jade Jones began her comeback from a knee injury with -57kg gold in the German Open.