FC Salzburg greatest success was reaching the 1993-94 UEFA Cup final as SV Austria Salzburg where they lost it vs FC Internazionale Milano, in that year they defeated 2 German cluubs in their route to play the final
This is the list of teams that FC Salzburg has played against German clubs in all their history at European competitions
Fortuna Düsseldorf (1980-81 UEFA Cup Winners’ Cup)
Eintracht Frankfurt (1993-94 UEFA Cup)
Karlsruher SC (1993-94 UEFA Cup)
FC Schalke 04 (2016-17 UEFA Europa League)
Borussia Dortmund (2017-18 UEFA Europa League)