The signing of the former England U21 left-back is complete.
Richards moved to England from Germany a year ago and signed a four-year deal at the City Ground.
Richards will join Forest's squad for Tuesday's friendly against Burton at the Pirelli Stadium.
Richards told Forest's official website that he was excited to return to England. There's great ambition for the return of the premier league for the club.
The City Ground is an amazing place that I can now call home after playing against Forest in the past.
There's more to come.
The transfer window will close at 11pm on September 1st.
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