Does anyone know a free website or app that is posting cheap business class flights? I've found many websites, but they are only posting cheap economy class fares. This page is the only one I know so far, https://www.flyertalk.com/forum/premium-fare-deals-740/, it's not bad, but the overview isn't the best.
I live in Europe, I know how to use flight search engines but they don't help to find offers. For economy flights for example I can look here https://www.urlaubspiraten.de/fluge . I am looking similar like this but for business class flights.