The long coat

A fact that isn't generally known about clothing in this era is that the long coat and narrow breeches was a style that originally came from England.

(This piece is paraphrased from Diana de Marly's excellent work on the clothing of the era 'Louis XIV and Versailles' Batsford 1987)

1666 was the year Charles II decided he should abandon French petticoat breeches and doublets and create a wholly English style. The Fire of London was seen as a judgement on his policy of submission to all things French and a new national style was needed. Tailors John Allen and William Watts were engaged to devise something wholly independent of the French influence. Charles had a preference for Spanish breeches and they felt a total concealment of the breeches with a coat was more moral. Therefore the English 3 piece suit was created with vest and coat in equal lengths above the knee. This simple style was launched in October 1666. The vests were initially plain but soon became decorated and the country followed suit with the notion that long vests were anti-French and anti Catholic. Louis XIV was not amused but pictures in the Almanach Royal (Louis XIV and the ladies of the Court) show that Louis tried the style by 1667. However Louis missed his flounces so soon went back to the old style which was more practical in the heat of the French summer. Charles II was persuaded to go back to short coats briefly but the cat was out of the bag and by 1678 the French were wearing long coats.
The painting by Flemish artist J Meunincxhove 'Charles II and James Duke of York in the Gardens of the Guild of St Barbe' (1671) shows Charles, anxious not to lose his French subsidy, giving up the English style under the orders of his sister Henriette Anne so as not to offend Louis XIV. He is wearing the French style again. The visit took place in 1656 though not painted till 1671.
Image which is zoomable from here