In A Tale of Two Cities, the French are pretty clearly divided into patriots and aristocrats. The patriots (peasants) must stand as a united front against the aristocrats (rich) if they ever hope to win a revolution to effect change. The Mender of Roads is clearly not an aristocrat, and he is clearly one of the poor peasants.
The Defarges take him to Versailles, the glorious palace of the King and Queen. They take him for one purpose--to make sure he is not swayed, later on, by all the finery and trappings of this luxurious lifestyle. We watch his eyes glaze over when he sees it all for the first time, and we understand that he will not be able to kill and destroy that which he finds so beautiful and impressive. The Defarges are quite sly with him, telling him as he's cheering madly for the royals:
"Bravo!...You are the fellow we want," said Defarge in his ear; "you make these fools believe that it will last for ever. Then, they are the more insolent, and it is the nearer ended."
After the Mender of Roads pauses to reflect, he agrees. The Defarges go on to use two analogies, dolls and birds, to further their point. They ask if he were given all the dolls or all the birds he could find and wanted to take some of their clothing or plumage for himself, would he not take the richest, brightest and finest? When he says he would, indeed, Madame Defarge replies:
"You have seen both dolls and birds to-day....now, go home!"
What they hoped to achieve was some disillusionment for the sumptuous appearance of the aristocracy, reminding him it was all trappings--trappings bought at the price of food on his table and clothes on his back.