"He bade me observe it, and I should always find,
that the calamities of life were shared among the upper and lower part of mankind;
but that the middle station had the fewest disasters.

(Daniel Defoe, Robinson Crusoe)

Not only does the word "bourgeois" refer to the middle class, it has some qualitative connotations as well.

It can be used for a respectable person with moderate wealth, whereas petit bourgeois would denote a person slightly less well-off. There is no notion of avarice inherent to it, though. In this case Scrooge would be a better choice. But mostly this word is used in an insulting way, because it can mean "profane" or "vulgar" as well. How come that this word can have meanings that seem almost contradictory? In the negative sense, the word "bourgeois" denigrates the mindset and attitude of a person. The security and solidity are not due to an artistic or scientific talent; There is narrow-mindedness, absence of dynamism and lack of rafinesse. In this case the bourgeois is all the contrary of an adventurer, connoisseur or savant.

The bourgeois is consequently by nature a creature of weak impulses, anxious, fearful of giving himself away and easy to rule.
(Hermann Hesse, Steppenwolf)

Hachette, Dictionnaire des synonymes
Cohen, The Penguin Thesaurus of Quotations