By car
Validation at one of the 8 road border crossing points:
5 border crossing points equipped with PABLO kiosks:
Saint-Louis (west of Basel; motorway; almost permanent customs presence).
Saint-Julien-en-Genevois (south of Geneva; near Bardonnex; almost permanent customs presence).
Vallard-Thonex (east of Geneva; motorway; near Annemasse et Etrembières; customs presence 6am-8pm).
La Ferrière-sous-Jougne (south of Pontarlier ; north-west of Lausanne ; near Vallorbe ; customs presence 6am-8pm).
Ferney-Voltaire (near Geneva-Cointrin airport; west of Geneva; customs presence 6am-8pm).
3 border crossing points without PABLO kiosks (validation by customs officer via electronic gun or manual entry of barcode digits):
Morteau / Col France / Col des Roches (Morteau sector; customs presence 6am-8pm).
Delle (east of Montbéliard; secteur of Territoire de Belfort; customs presence 6am-8pm).
La Cure (north of Geneva; sector of Jura / Les Rousses; customs presence 6am-8pm).
Note: at border crossing points equipped with PABLO terminals, some terminals may be deactivated or inaccessible outside operating hours.
By train (including TGV Lyria)
General rule: validation during customs control carried out by French customs officers in the train (however this control is not systematic, and customs officers are sometimes dressed in civilian clothes)
If arriving at Geneva-Cornavin station: validation at the French customs desk at the train station.
Absence of French customs officers: see paragraph below.
Absence of French customs officers at road border crossing or during train travel
Presence of Swiss border guards: they will stamp your tax-free forms and hand them over to French customs for final validation (be sure to take a photo of the stamped form before leaving it to the Swiss customs).
Absence of Swiss border guards:
Place your tax-free forms and your proof of purchase (i.e., the ZappTax resale invoice that accompanies the tax-free form) in one of the many “declaration boxes” (“boîtes à declaration”) spread throughout Switzerland (at border crossings, train stations, etc.).
Swiss customs will stamp your forms and forward them to French customs for final validation.
More info on declaration boxes:
In this case, you are supposed to attach to your form a "declaration of import into Switzerland" (form available in a small specific box attached to each declaration box -> see illustration above).
Specific situation of central train station of Berne ->there is no declaration box -> 3 solutions:
Place the tax-free forms in a declaration box when stopping at Basel train station.
Place the tax-free forms in a declaration box elsewhere in Switzerland (there is one at Bern-Belp airport).
Use the "a posteriori" validation procedure (see question « I was unable to validate my tax-free forms when I left. What can I do? ».