Radlers definitely tend to be sweeter rather than sour. By most generally accepted definitions a radler is half lager/half lemonade. Cascade Brewing in Portland on SE Belmont makes some of the best sour beers available. If you like sours you owe it to yourself to hit up their barrel house. They always have between 8-10 sours on tap.Where I lived in Germany (Hesse) citronade was what we call lemonade. Lemonade wad a citrusy carbonated soft drink along the lines of 7-Up or Sprite. The Radler I tried tasted like Helles and Sprite.
The France paragraph is equivalent.
Old Horst calls it lemonade at first but if you read down he says lemon soda, and says you can make your own by mixing beer and lemon soda.
A British born woman down the street once talked about how she was confused when she had "cider" here for the first time. She was expecting an alcoholic drink, not fresh pressed apple juice.