How does George Orwell portray poverty in 'Down and Out in Paris and London'?

In Down and Out in Paris and London, published in 1933, Orwell chooses to live the life of a poor person. He writes:

It is a feeling of relief, almost of pleasure, at knowing yourself at last genuinely down and out. You have talked so often of going to the dogs—and well, here are the dogs, and you have reached them, and you can stand it. It takes off a lot of anxiety.

In  Paris, after pawning almost everything he owns, Orwell becomes a waiter at a large, fancy hotel patronized by wealthy people. He describes in great detail the long, hard hours, miserable conditions, and endless dirt that surrounds the food preparation. It is two different worlds on either side of the kitchen door. He describes, for example, how fast the waiters must race around, running up and down steps and through back corridors to deliver room service breakfasts to the wealthy patrons. Things are so rushed that if they drop a piece of buttered toast face down on a dirty floor, they just pick it up, brush it off, and serve it anyway. He records coming into work one day to see a rat munching on the ham sitting on the counter that will later be served to the rich guests. His point is that nobody is really served in a situation that makes the life of the poorest workers so hard and miserable that they cannot do their jobs in a sanitary way.

In London, Orwell becomes a tramp, joining the beggars, almost entirely men, who are wandering the countryside. He notes that, like being a waiter, begging is hard work, and, really, no different from respectable work. He says, 

Then the question arises, Why are beggars despised?—for they are despised, universally. I believe it is for the simple reason that they fail to earn a decent living. In practice nobody cares whether work is useful or useless, productive or parasitic; the sole thing demanded is that it shall be profitable.

Orwell wants to show us that the poor are not the "other," they are ordinary people just like us who have had bad luck or who have been denied opportunity. They do not "deserve" to be poor; they work hard at surviving, and they should not be unfairly stigmatized and treated cruelly for being poor. He writes that it is important and necessary for a person with no education to have work, because such people have no inner resources to fall back on if they do not have a job.

What is Orwell's opinion of beggars in Down and Out in Paris and London?

Orwell interacts with beggars at length when he is down and out in London. He defines beggars as people, usually men, who trade on the appearance of misery to sell matches or other small items, do some small entertaining tricks out in public, or simply ask for monetary assistance to survive. Their survival is almost always marginal: beggars are on the very fringes of society.

Orwell's opinion of beggars differs, however, from that of most of his society. He considers them ordinary human beings earning a living, if poorly, just like anyone else. He is aware, though, that most of society despises beggars as useless parasites and considers them different from the masses of decent people.

Orwell asks why this is the case. He says that beggars, like other laborers, stand outside for long hours for low pay:

getting varicose veins, chronic bronchitis, etc. It is a trade like any other; quite useless, of course—but, then, many reputable trades are quite useless.

In fact, Orwell argues, beggars do a lot less harm than many people in reputable trades. They are parasites, he admits, but so are many people who earn far more doing worthless things that provide no real societal benefit. In fact, because they earn so little, beggars at least are not too much of a drag on society's resources.

Orwell concludes that beggars are despised because they are poor. They can't turn a profit or grow rich, so they are looked down upon. In fact, Orwell says, they should be honored, because they suffer quite a bit for very little return.

How does George Orwell explore social classes and class consciousness in Down and Out in Paris and London?

In Down and Out in Paris and London George Orwelll explores social class and the theme of class consciousness and class separation by having an objective narrator who is well educated enough to remain dispassionate and analytical as he, through varying circumstances, sinks into the underground impoverished classes in Paris and then London. The final message Orwell brings is that poverty is degrading and destructive to body and soul, and circumstances are worsened because authorities have no concern for the poor neither do authorities have a means to provide succor for the impoverished, who are left to wander the streets--where permitted--and sink into tuberculosis and other irremediable illnesses.

The narrator's journey into the underground, where class separartion is at its apex, is recorded with the clarity and precision, as one critic puts it, of the camera lens, therefore a sound exploration of social class and class consciousness is present. Down and Out would be informatively augmented by the 1952 film Sister Carrie starring Laurence Olivier as the successful maître d' who loses all and eventually sinks into the underground of New York and into death.