Financial Times has this chart up about the voters for the National Front, which is Marie Le Pen's party.
I find the chart very hard to decipher, even though I usually like the dot plot format.
The first thing to figure out is not visual. It's a definition of the data. The average voter represents those who voted in the 2015 regional election. The National Front voters are those who intended to vote in 2015, and these are sub-divided into "loyal" and "new" voters. All it takes one to be "loyal" is to have voted for the National Front in 2012; all others are "new."
All of the above information you pick up primarily from the footnotes, combined with various parts of the title, and legend. Similarly, you also learn that FN is the acronym for National Front.
This following version is clearer:
The new version mostly just re-orients the original chart, turning it on its side. It's quite surprising how much better I feel about it. I think it's because the message is primarily about the relative ages, and in the original chart, aging is portrayed downwards, which is not natural.