What has happened to Ragueneau at the beginning of Act 3 in Cyrano?
In short, poor Ragueneau has lost all his money in his efforts to publish his book of poetry, "Ragueneau's Rhymed Recipes." Further, Ragueneau has also lost his wife, Lise.
In the play, Ragueneau is both a baker and a poet who lets already established poets into his bakery to eat for free if they listen to his newest verses. He is a good friend to Cyrano (and remains so). Not only does Cyrano get to listen and eat pastries for free, but Cyrano is allowed by Ragueneau to meet with Roxane at his bakery. It isn't long before Ragueneau is warning Cyrano about making lots of enemies. The irony is that Ragueneau has made an unlikely enemy himself: his wife, Lise. Lise is disgusted with Ragueneau for neglecting his pastry shop in favor of his poetry book, so she leaves him for a musketeer.
By the end of this play, Ragueneau is simply working odd jobs around the town because he no longer owns his pastry shop (and has lost his wife as a result of his poetic exploits). However, Ragueneau remains loyal to Cyrano until the end.