Earlier there were two different titles for a woman in Germany, either "Frau" for a married woman or "Fräulein" (little Mrs) for an unmarried woman. On the other hand there was just "Herr" for a married or unmarried man. Nowadays "Fräulein" isn't used anymore. Every woman, married or not, gets the title "Frau".
Sometimes you can hear older people still use "Fräulein" because they are used to it, but it's really out of official use now.