During a scene where the Musketeers are fighting in a Paris marketplace, a stall is displaying orange carrots for sale. In the 17th Century (when the Musketeers' story is set) orange carrots were a novelty. Before the 17th Century, carrots were white or purple. Orange carrots were first cultivated in the Netherlands and their colour was taken as symbolically supportive of the Protestant House of Orange. Though France was Catholic there may have been some sympathy with Netherlands Protestants as William of Orange had led rebellion in the Netherlands against its then-Spanish rulers (and the Spanish were, of course, France's enemies during this period).
However production staff chose orange carrots because 90% of viewers have never seen white or purple carrots and they didn't want viewers distracted from the story by wondering what the white and purple things were.
Part of the action takes place in a field of maize. Maize was not introduced to Europe until the 15th/16th centuries.
Luke Pasqualino (D'Artagnan) & Marc Warren (Rochefort) also worked together on Snatch (2017) as Albert Hill & Bob Fink respectively.
Marc Warren (Rochefort) & Tom Burke (Athos) also worked together on State of Play (2003) as Dominic Foy & Syd respectively.