Stern von Prag is listed as a Hybrid Rugosa by Kordes:

Stern von Prag, Berger 1924, 80cm, crimson red, for group planting or hedge, repeat blooming, large, Hybrid Tea-type bloom, fragrant

Source: Wilhelm Kordes, "Rosen - Züchtung, Anpflanzung und Pflege", Frankfurt (Oder) & Berlin, 1932