At Agincourt - White Hoods of Paris by George Alfred Henty

The story begins in a grim feudal castle in Normandie. The times were troublous, and soon the king compelled Lady Margaret de Villeroy, with her children, to go to Paris as hostages. Guy Aylmer went with her.Paris was turbulent. Soon the guild of the butchers, adopting white hoods as their uniform, seized the city, and besieged the house where our hero and his charges lived. After desperate fighting, the white hoods were beaten and our hero and his charges escaped from the city, and from France. (Summary from the original back cover)