I'd like to translate the following sentence : "ne sera certifiée qu'à la réception des arrhes"...
Should I say : "certified upon the deposit reception" or "certified upon the reception of the deposit" ?
I would most likely translate "à la réception" as "upon/on receipt" here.
Note that "ne sera certifiée qu'à la réception des arrhes" is not a sentence.
As a result, and because you have provided no context, we have no way of knowing what it is that will be certified or whether you're referring to
"a security deposit" (for apartment rentals perhaps?) or some other kind of advanced payment.