Sentence:  This is that famed Martial law, with its Red Flag, its 'Drapeau Rouge:' in virtue of which Mayor Bailly, or any Mayor, has but henceforth to hang out that new <WSD>Oriflamme</WSD> of his; then to read or mumble something about the King's peace; and, after certain pauses, serve any undispersing Assemblage with musket-shot.... 
Meaning of the word marked with <WSD> tags:  Something resembling the banner of St Denis; a bright, shining object.