In my experience History and French are indeed hard A Levels, particularly French because in your final exam you're required to write a 1500 word essay that require literature analysis similar to that of an English A Level, but in French. Consequently for somebody who is inclined to languages but isn't overly great at literature, it's very difficult. Also the jump from AS to A2 in French was vastly greater than any other subject I did.
As for History, the jump from AS to A2 isn't that huge, however the workload at A2 was probably the biggest out of any subject I did. I can only talk about the subjects that I did (History, French, Politics + AS Economics), however I think the Independent is spot on in saying that History and French are two of the hardest A Levels.