Before leaving Málaga I met Rocio Gonzalez, 30, a member of the 15M Movement that brought hundreds of thousands on to the streets across Spain this weekend. We spoke shortly before Saturday's gathering in Málaga's main Plaza de la Constitución – the last major 15M protest there, in June, before the holidays, saw 25,000 people occupy the square.

The nationwide movement, which grew out of the Madrid 15 May protest, is avowedly local and non-hierarchical, and I was intrigued by how this actually functioned. Besides its over-arching, general demands – truly participative democracy, an end to corruption, a tax on financial transactions, a government that works for the good of all rather than the profit of a few – how does 15M actually work on the ground?

Rocio said that in Málaga, neighbourhood committees met locally at least once a week across the city, discussing strictly neighbourhood issues. Each could be attended by up to several dozen people, she said. And in Constitutión Square, gatherings were held most weekday evenings.

These are either twice-weekly citizens' assemblies for all, typically drawing around 100 people, or smaller meetings of 15M's city-wide special commissions, which hammer out – among other things – its stance on communication and media, culture, education, ecology, immigration, equality, labour, health, university, housing and action.

"It's very hard, I have to say," Rocio said. "There's a lot of talking, and a lot of voting. We vote all the time, on everything. It takes a lot of time. But it's essential, if we are to demonstrate that the way politics is run at the moment isn't the right way."

In Spain, she said, the existing system had failed because "so many politicians are really only interested in filling their pockets, and staying in power. They specialise in the kind of vanity politics, big empty gestures, that they think will help get them re-elected," she added.

15M Málaga's demands to the city council include: an immediate end to evictions; proper care of the city's squares, parks and gardens; better road cleaning and more recycling bins; improved public transport; investment in education at all levels; closer co-operation with neighbourhood associations on grievances; the promotion of ethical banks and credit unions.

"It's about demanding that the city authorities do what they are supposed to do," she said. "Spend money wisely, for the good of all the people, make sure their citizens have what they really need, not sidewalks made of marble like they have in Marbella. It's about really looking after people, doing a proper job – the complete opposite of what so much politics is actually about right now, in fact. I mean, why don't we have cycle paths in Málaga? Why don't we have trains and buses that run later into the evening? It's just common sense, really."

Rocio, who works on a local tourism publication, is optimistic, she said, "because I have to be, but also because I see how bad this crisis really is. There have been crises in Spain before, in 1982, 1990, but nothing like this. Here, in Málaga, unemployment is climbing every month – 6,000 more people this month – and we have families going hungry. In Spain, in the 21st century! It's just so wrong."

And she's confident too, she said, because "the politicians are going to have to take notice of us. We really have a base, now. All ages, all sections of society. The first 15M Málaga assembly I went to, there were pensioners, students, shopkeepers – elderly women of 80! It brought me out in goosebumps, it was so marvellous. They'll have to sit up and listen."

• If you have a story to tell, know a person I should talk to or live in a place you think I should visit, please contact me: jon.henley@guardian.co.uk, or @jonhenley (the hashtag for this venture is #EuroDebtTales)