He had his house to think of.

He swore that they should not fight on his premises, and implored them in the same breath not to attempt it.
At that Garnache, now thoroughly on his guard! was for putting off the encounter.
"Monsieur Courthon," said he--and he felt a flush of shame mounting to his brow, and realized that it may need more courage to avoid an encounter than to engage in one--"there is something that in the heat of passion I forgot; something that renders it difficult for me to meet your friend at present." Courthon looked at him as he might look at an impertinent lackey.
"And what may that be ?" he inquired, mightily contemptuous.

There was a snigger from some in the crowd that pressed about them, and even Monsieur Gaubert looked askance.
"Surely, sir," he began, "if I did not know you for Monsieur de Garnache--" But Garnache did not let him finish.
"Give me air," he cried, and cuffed out to right and left of him at the grinning spectators, who fell back and grinned less broadly.

"My reason, Monsieur de Courthon," said he, "is that I do not belong to my self at present.

I am in Grenoble on business of the State, as the emissary of the Queen-Regent, and so it would hardly become me to engage in private quarrels." Courthon raised his brows.
"You should have thought of that before you rolled Monsieur Sanguinetti in the mud," he answered coldly.
"I will tender him my apologies for that," Garnache promised, swallowing hard, "and if he still insists upon a meeting he shall have it in, say, a month's time." "I cannot permit--" began Courthon, very fiercely.
"You will be so good as to inform your friend of what I have said," Garnache insisted, interrupting him.
Cowed, Courthon shrugged and went apart to confer with his friend.
"Ah!" came Sanguinetti's soft voice, yet loud enough to be heard by all present.