Oh gosh, I've just googled it[1], and I'm really glad we don't have such monsters.
French ballots are really straightforward [2], with just one name written on it.
To count them, the volunteers are grouped by tables of four: two people (alternatively) open an envelop containing one ballot, read the result aloud and put on a stack in the center of the table. Then the two remaining people independently note the score. In the end, the ballots and the envelops are re-countered and we check that it matches the sum of the candidate's scores. The ballots (and the envelops) are then stored in sealed bags.
The ballots aren't centrally checked unless a complaint is made by someone, suspecting fraud in their polling station.
In my city, we usually have around 30 people counting, and the process only take one or two hours.
Separately from our monstrously large Senate ballot papers, which are ultimately scanned and computer-counted at the central counting centre, our much smaller House of Representatives ballot papers still use preferential/instant-runoff voting.
The nature of preferential/IRV systems requires that ballot papers be counted centrally for the entire district, as distribution of preferences needs to take into account all ballots from all polling places. However, we still conduct a preliminary count in each polling place which is used among other things for media purposes. The full, definitive count is a lengthy process which can take weeks, and is conducted centrally - also including postal ballots and absentee ballots from other parts of the country.
The same staff who are responsible for counting ballots at the end of the day are also responsible for setting up the polling place and issuing ballots throughout the day, which requires some procedural training especially for officers responsible for issuing absentee ballots and things like that. At the polling places I've worked at, we've usually had 1000-2000 voters come through on election day, and would have 5-10 staff working there. Counting and polling place packup usually takes us 3-4 hours.
(Also if you think the ballot paper image you linked was big - I refer you to https://www.flickr.com/photos/heritagefutures/5560654939, which shows 311 candidates running for the New South Wales Legislative Council in 2011.)
Oh gosh, I've just googled it[1], and I'm really glad we don't have such monsters.
French ballots are really straightforward [2], with just one name written on it.
To count them, the volunteers are grouped by tables of four: two people (alternatively) open an envelop containing one ballot, read the result aloud and put on a stack in the center of the table. Then the two remaining people independently note the score. In the end, the ballots and the envelops are re-countered and we check that it matches the sum of the candidate's scores. The ballots (and the envelops) are then stored in sealed bags.
The ballots aren't centrally checked unless a complaint is made by someone, suspecting fraud in their polling station.
In my city, we usually have around 30 people counting, and the process only take one or two hours.
[1]: https://c2.staticflickr.com/4/3783/9557893855_135143ce49_b.j... [2]: https://upload.wikimedia.org/wikipedia/commons/d/dc/France_%...