Unfortunately I don't have a taxonomy book ready for use....
https://en.wikipedia.org/wiki/Flea
https://en.wikipedia.org/wiki/Human_flea could it be Pulex irritans?
(cf. also image at http://www.familie.de/gesundheit/flohbisse-541137.html )
or could it be that you found a flea which are found to inhabit animals (cats,dogs, etc.): Pulicidae | Ctenocephalides
(dog flea: cf. eventually also images found at: http://www.hundefloh.eu/Gefahren.html or http://www.wissen.de/lexikon/hundefloh , https://bildagentur.panthermedia.net/m/lizenzfreie-bilder/1016933/hundefloh-portrait/ )