How do you write 400 francs?

To write 400 francs, you can simply express it as "400 francs" or use the abbreviation "400 CHF," where CHF stands for Swiss francs. If you're writing it in a sentence, you might say, "The total amount is 400 francs." Additionally, if you're using a currency symbol, you can write it as "₣400" or "400₣."