I’ve never heard “no risk, no champagne,” but the meaning seems clear, and I like the sound of it :) We usually say “no risk, no reward (or 'no glory'),” “no pain, no gain,” or “nothing ventured, nothing gained.” BTW, I notice that “champagne” rhymes with “gain” in English….

They might understand, but it would be clearer to use "No risk, no gain" for clarity (possibly that's where your example was derived from). There is the risk you'll fumble on your delivery, and you'll have to explain yourself again.