What is true of it
Dm7♭5 is D, F, A♭ and C — 1, b3, b5 and b7 counted from D.
These are also the notes of Fm6/D. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
The easiest of the 1 fingering below is 7888: 4 fingers, held at the 7th fret.
None of them uses an open string, so this chord moves up the neck unchanged — the same shape 1 fret higher is the chord a semitone above.
Where its notes are on the neck
The brass dots are D, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
Dm7♭5/F
acab
Dm7♭5/A♭
1213
Dm7♭5/C
5545
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.