Vegan and Vegetarian are on the menu, but the same kitchen also prepares what you avoid, so cross-contamination is possible. Tell staff what you react to, and ask how your dish is prepared before you order.
A café and bistro in the Alsergrund where the whole premises is gluten-free and lactose-free, with vegan and sugar-free choices. Milk protein may still be present, so this is a lactose claim and not a dairy-free one.