Yeah I recall that too from books going back a long long time. I thought it was at one time considered that the Germani tribe were actually Celtic.
That would make sense I suppose. You do get coincidences of ethnonyms.
Even googling I am not finding much about it. I have definately seen this Iberian Peninsula Germani on tribal maps in books in the past. I think too it was southern Iberia somewhere. SE Iberia rings a bell. I think some speculation about the Belgae was made but my memory if foggy on this.