When Chinese voters go to the polls, it is only to pick local representatives to advise on mundane issues like rubbish collection and parking. But when Ye Jinghuan sought election in Beijing, she was treated like an enemy of the state.

Plainclothes officers tailed the 64-year old retiree as she left her home on polling day Tuesday, and she faced constant harassment from police and government officials after announcing her run, she said.

The nationwide contest for spots in local legislatures, held every five years, is the only direct election in the People's Republic of China.

Authorities were eager to show off what they describe as democracy "with Chinese characteristics", with officials ushering dozens of reporters into a polling station in Xingfu, in central Beijing.

Voters filled out their pink ballot papers in front of officials, ignoring a screened-off area labelled "Secret Balloting Place".

Chinese law states that anyone over 18, who has not been stripped of their political rights, can stand for election and vote.

"Ethnicity, gender, party, residence, economic situation, there are no limits," crowed Liu Xiancai, who heads the Xingfu election office.

But Ye's experience was different.

Candidates must be backed by 10 people or nominated by their workplace to stand. But official election committees ultimately decide who gets on the ballot.

"The government can't let someone like me be a candidate," Ye said. "I would express my own thoughts. When the people's congress opens session, I would cast an opposition ballot."

- Tightening control -

Ye's platform was simple: better controls on traffic, more elder care facilities, and making it easier for constituents to contact their delegates.

But her seemingly innocuous ideas provoked a strong reaction from local police, who closely monitored her behaviour and prevented her meeting foreign media.

The authorities' response to Ye indicates how China is tightening controls on even anodyne political expression, said Yaxue Cao of Chinachange.org, a US-based website advocating for increased democracy.

A key meeting of top Communist leadership in October called for increased ideological discipline and warned ruling party members against criticising the official line.

In a pyramidal system, the elected local representatives choose municipal delegates, who choose provincial legislators, who in turn select members of the national parliament -- which is widely expected to hand Communist party General Secretary Xi Jinping a second term as president in 2018.

Tuesday's election is "very low-level, grassroots", Cao said, adding "there really isn't much you can do to push for political reform".

But "even on this useless grassroots level, simply by stating you're an independent candidate, you're challenging them".

Almost all the 21,765 candidates on ballot papers across Beijing came from the ruling party, with a token few from China's eight other official parties, none of which oppose communist rule.

Authorities had thwarted around 20 other independent campaigns in the capital, Ye told AFP by phone, adding it was "not safe" for anyone to put their name to her nomination.

- Democracy a threat -

Red banners around Beijing proclaim that the local elections are the "foundation" of China's system of governance, but the weeks leading up to the polls saw no rallies, no eager candidates glad-handing voters or campaign posters.

Last week around 50 mostly elderly voters gathered in a community centre basement in one of Beijing's ancient hutong neighbourhoods to meet the district's official candidates.

The three competitors for two seats spoke briefly about their backgrounds, but spent almost no time discussing issues beyond a neighbourhood beautification campaign.

Questions from the audience focused on practical aspects of daily life and there was little discussion of larger political questions, such as the government crackdown on corruption under Xi or the nation's widening income gap.

Only one woman, a retiree in her 60s, expressed dissatisfaction with China's direction: "The government is failing to meet our needs at every level," she said to a smattering of applause.

There is no room for such dissent on the ballot: the Communist party has described multi-party democracy as an existential threat, and state media have savaged the circus atmosphere of this year's US presidential election.

Earlier this month, plainclothes police broke up Ye's campaign event in western Beijing, turning away several supporters and two AFP reporters.

China's elections are "not the same as the West", an elderly man proudly told reporters as he left the polling station in Xingfu Tuesday. "The government is under the leadership of the Communist Party."