“What offence has he committed?” I asked, eager to learn some fact to his detriment.

“He keeps well within the bounds of the law,” my companion answered. “Nevertheless he is utterly unscrupulous and most ingenious in his methods. He is reported to be chief of the section of Secret Police attached to the Russian Embassy, but they are a mysterious lot of spies, always coming and going. Sent here from St Petersburg, they remain a few months, watching the revolutionary refugees, and then go back, their places being taken by a fresh batch.”

“Why is Renouf in Paris? Have you any idea?”

“None, m’sieur,” Monsieur Goron answered. “He has been absent fully six months, and only last night I met him coming out of La Scala.”

“Did you speak?”

“Yes. He did not, however, recognise me,” smiled the Chief of Police. “I did not expect he would, as I chanced to be acting as a cabman, and was sitting upon my box outside the theatre. He hailed me, but I refused to drive him. I was waiting for a fare who was enjoying himself inside, and who, on coming out, I had the pleasure of driving straight to the Préfecture,” added the man of a thousand disguises with a chuckle, swallowing his cocktail in one gulp.

“Where does the Grand Duchess live?” I inquired, after a slight pause.

“Deedes is simply gone on her,” cried Cargill, with good-humoured banter. “He evidently wants to take her out to dinner.”

“No,” I protested, smiling grimly. “Nothing of the kind. I only want to know whereabouts in the Avenue des Champs Elysées she lives.”

“It is a large white house, with green jalousies, on the left-hand side, just beyond the Avenue de l’Alma,” explained the Chief of Police, laughing at Cargill’s suggestion.