In most cases, no.
The app automatically generates the tax-free forms, which are available in the Zapptax app and also sent by email. The customer can then validate them electronically, either at a kiosk or with a customs officer.
However, if the customer leaves the EU from a different country than the one where the purchase was made, they must print the forms and have them manually stamped by a customs officer.
After that, they need to upload a photo of the stamped form in the app.
Examples where printing is required:
Purchase in France, flight departing from Amsterdam or Brussels.
Purchase in Belgium, flight departing from Paris Charles de Gaulle.
Purchase in France, Eurostar departure from Brussels-Midi station.