What information does Defarge receive from Jacques of the police force? (Book 2 Chapters 14-16)

A policeman tells Monsieur Defarge that there may be an English spy stationed in Saint Antoine named John Barsad, supplying a physical description of him....The next day, Madame Defarge recognizes Barsad when he enters the shop. A rose lies beside her on her table, and when he enters she puts it in her hair and everyone else leaves the shop. Barsad chats with her about the cognac he orders, and he tries to trick her into complaining about poverty or about Gaspard's execution. From this reference it becomes clear that Gaspard is the prisoner who was mentioned in the previous chapter.