Learn Hardcore French: Sur le trottoir, une piétonne lit un panneau sur la prochaine manifestation. - On the sidewalk, a female pedestrian reads a sign about the next demonstration.

Sur le trottoir = on the sidewalk / on the pavement (physically located on its surface).
Dans le trottoir would literally mean inside the sidewalk, which doesn’t make sense.
Au trottoir is not idiomatic; you say au bord du trottoir (at the edge of the sidewalk), but not au trottoir alone.

So whenever you mean “on” in the sense of “on top of / on the surface of,” French usually uses sur.

Why is there a comma after Sur le trottoir?

Sur le trottoir is an introductory location phrase, like English On the sidewalk at the start of a sentence.

French often separates such fronted phrases with a comma:
- Sur le trottoir, une piétonne lit un panneau.
- Ce matin, il pleut. – This morning, it’s raining.

You could also put it at the end, without a comma in the middle of the sentence:

Une piétonne lit un panneau sur le trottoir.

Both are correct; the version with the comma just emphasizes the location first.

What is the difference between une piétonne and un piéton?

Both mean pedestrian, but:

un piéton = a male pedestrian (or grammatically masculine generic form)
une piétonne = a female pedestrian (feminine form)

The -ne ending is a common way to form feminine nouns from masculine ones:

un patron → une patronne
un lion → une lionne

In the sentence, une piétonne tells you explicitly that the person is female.

If I don’t know the gender of the pedestrian, should I use un piéton or une piétonne?

By default, French traditionally uses the masculine form when the gender is unknown or not specified:

Un piéton lit un panneau. – A pedestrian is reading a sign.

So un piéton is the neutral “default” in many contexts.
You only use une piétonne when you want to say clearly that the pedestrian is female.

Why is it un panneau and not une panneau?

French nouns have arbitrary grammatical gender that must be memorized.

un panneau is masculine, so it takes un (a / one).
You cannot say une panneau; that’s grammatically wrong.

Panneau can mean:

a road sign: un panneau de signalisation
a notice or information board: un panneau d’affichage
a panel, a board (e.g. wooden board or control panel)

Here, from context, it’s a sign or notice board.

Does panneau always mean “sign,” or are there other words like enseigne?

Panneau is a broad word for sign or board:

un panneau de circulation – a traffic sign
un panneau d’affichage – a noticeboard / display board

Une enseigne is more specifically a shop sign / store sign / brand sign:

une enseigne lumineuse – a neon sign
une grande enseigne – a big retail chain

So for a street or protest information sign, panneau is the natural choice, not enseigne.

In un panneau sur la prochaine manifestation, what does sur mean? Is it literally “on”?

Here sur means about / regarding, not physically “on top of.”

un article sur la politique – an article about politics
un documentaire sur les animaux – a documentary about animals
un panneau sur la prochaine manifestation – a sign about the next demonstration

So sur can mean “on” in the sense of “on the subject of.”

Why is it la prochaine manifestation and not manifestation prochaine?

In French, many common adjectives go before the noun, especially:

B eauty: beau, joli
A ge: jeune, vieux, nouveau
N umber/quantity: premier, plusieurs
G oodness: bon, mauvais
S ize: grand, petit

Prochain / prochaine often goes before the noun when it means next in time:

la prochaine manifestation – the next protest (coming up chronologically)
la prochaine fois – next time

La manifestation prochaine is possible but sounds more formal/literary and can feel like “the forthcoming demonstration” rather than the plain “next one.” In everyday speech, la prochaine manifestation is the natural phrase.

Is manifestation a “false friend”? Does it really mean “protest/demonstration”?

Yes, manifestation is a common false friend.

une manifestation most often means a demonstration / a protest in French.
English manifestation (as in “a manifestation of anger”) is more often une manifestation de colère, une expression, or une manifestation in certain abstract contexts, but that’s more formal.

In everyday French:

Il y a une manifestation demain. – There’s a protest/demonstration tomorrow.
participer à une manifestation – to take part in a protest.

So in this sentence, it clearly means a protest / demonstration, not the English abstract “manifestation.”

Why is prochaine before manifestation and also feminine?

It agrees in gender and number with the noun.

manifestation is feminine singular → la manifestation
prochain(e) must match it → la prochaine manifestation

If the noun were masculine:

le prochain concert – the next concert
le prochain train – the next train

And plural:

les prochaines manifestations – the next protests
les prochains trains – the next trains

So position: before the noun;
form: feminine singular to match la manifestation.

Why is it lit and not lis or lisent? How is lire conjugated here?

Lit is the 3rd person singular present tense of lire (to read):

je lis – I read
tu lis – you read (singular, informal)
il / elle / on lit – he / she / one reads
nous lisons – we read
vous lisez – you read (plural/formal)
ils / elles lisent – they read

Here the subject is une piétonne (she), so:

une piétonne lit un panneau – a (female) pedestrian is reading a sign.

How would the sentence change if the pedestrian were male or if there were several pedestrians?

Male singular:
- Sur le trottoir, un piéton lit un panneau sur la prochaine manifestation.
Female plural:
- Sur le trottoir, des piétonnes lisent un panneau sur la prochaine manifestation.
Mixed or male plural (generic masculine):
- Sur le trottoir, des piétons lisent un panneau sur la prochaine manifestation.

Notice the changes:

un / une / des with piéton / piétonne / piétons / piétonnes
lit (singular) → lisent (plural) to agree with the subject.