What is the highest number of crowns someone can get from one tree?
per skill, the poster is asking for the whole tree. For the French tree, there are 96 skills times 5 crowns each + 3 possible crowns for the bonus skills which are done at 1 crown each (Flirting, Idioms and Christmas) So that is 480 plus possibly 3 more. If you bought all the bonus skills, it would be 483 possible crowns.
You can get up to five in any skill except the bonus skills which only have one level. The total "crown level" shown at the top of the page is just all of the individual skill added together, so the longest tree will likely have the most crowns available. Is that still Norwegian? The German one apparently tops out at 608 with all of the bonus skills.
Wow, I didn't realize that Norwegian had 117 skills, not including any bonus skills at all! So that looks like 585 crowns, if there are no bonus skills. I thought German was the longest one, but I had never counted them before. German has 121 regular skills x 5 crowns is 605 crowns and German does have 3 bonus skills, so Wow again!