If I’m not mistaken, re-frame predates flux

Don't know the history exactly, but seems like re-frame did get inspired by at least some bits from flux: http://day8.github.io/re-frame/historical/#what-is-the-problem

Flux was not a central influence. But it was part of the over mix.

"Can we say that re-frame is en implementation of the flux architecture ?" Well, they both: • create an in-memory "store" distinct in design from the views they support; • offer one-way state flow where derived values depend on others; and • they both restrict state change to pre-defined operations on that state; and • the above summarizes the Flux pattern, so I would say yes.