It is essentially a philosophical concept — the tangible, the immediately perceptible — but in this context we want to avoid an over-philosophical rendering while at the same time trying to capture the positive connotations of the experience it is evoking. I think maybe "the here and now" might serve the purpose: the idea of what is immediately here in front of us right now.

It is strongly associated with that which can be perceived with the senses:

"Emploi subst. masc. avec valeur de neutre. Le concret. Ensemble des choses concrètes. "
http://www.cnrtl.fr/lexicographie/concret

There's a curious Wikipedia article on this containing a single quotation, including the following:

"Le concret, c'est le domaine des significations familières qui est la marque du monde où nous vivons, plus particulièrement du monde perçu. On entend généralement par concret ce qui existe réellement, ce qui est donné aux sens (une idée peut être concrète si elle est le résultat immédiat de la perception)."
https://fr.wikipedia.org/wiki/Concret