Consumers in Austria pay more for the same products than consumers in Germany.

Omissions

• The claim is a generalisation: the 'Österreich-Zuschlag' is documented above all for identical branded groceries and drugstore products (AK Preisradar), not necessarily for every product category or for all consumer goods, so 'products' in general overstates the uniformity of the effect.
• The most prominent evidence (Arbeiterkammer Preisradar/Preismonitor, ~26% on average for identical groceries) is produced by the Austrian Chamber of Labour (AK), an advocacy organisation representing workers and consumers, which has an institutional interest in highlighting this surcharge; the figure is not a neutral official statistic.
• The claim conflates a competition/price-discrimination issue (manufacturers preventing retailers from buying cheaper goods in other EU countries) with a breach of the single market; whether it constitutes a legal infringement of single-market rules is a legal/political interpretation, not a verified fact.

Sources

• PrimaryArbeiterkammer Wien — PreisradarEinkaufen ist in Österreich um durchschnittlich 26 Prozent teurer als in Deutschland. Einzelne Marken-Produkte kosten sogar fast ums Doppelte mehr. (Shopping in Austria is on average 26 percent more expensive than in Germany. Individual branded products cost almost twice as much.)
• PrimaryArbeiterkammer — AK Preismonitor press release (OTS)Einkaufen ist in Österreich um durchschnittlich rund 26 Prozent teurer als in Deutschland. Einzelne Marken-Produkte kosten sogar fast ums Doppelte mehr.
• Secondaryhelp.ORF.at — Warum gleiche Produkte in Österreich teurer sindIm Schnitt seien idente Lebensmittel um 26 Prozent teurer als in Deutschland, kritisiert die AK den 'Österreich-Aufschlag'. Einzelne Waren ...
• Secondaryvienna.at — AK study: Food in Austria up to 93 percent more expensive than in GermanyOn average, identical groceries are 26 percent more expensive than in Germany, criticizes the AK for the 'Austria surcharge'.
• Secondaryfoodwatch Österreich — Österreich-AufschlagDer Österreich-Aufschlag entsteht, wenn Hersteller verhindern, dass Händler günstigere Produkte aus anderen EU-Ländern einkaufen und in ... (The Austria surcharge arises when manufacturers prevent retailers from buying cheaper products from other EU countries...)