The British No. 1 lost three service games in the first set, but was able to secure four breaks of her own to take the set in 40 minutes.
The No. 26 seed wrapped up victory against Lottner, 22, after winning a second set that also lasted 40 minutes and produced the same 6-4 scoreline as the previous set.
Konta is not known to be particularly adept on clay, and in four previous attempts had never succeeded in getting past the first round at Roland Garros, but she is currently in fine form on the surface. The Brit finished as runner-up to world No. 2 Karolina Pliskova at the Rome Masters two weeks ago, with wins over Venus Williams and top 10 seeds Sloane Stephens and Kiki Bertens on the way to the final.