Un incendie commence dans un vieux bâtiment près de la place.

Both can translate as fire, but they are not interchangeable:

• un incendie = a serious, destructive fire, usually unwanted and damaging: a house fire, a forest fire, a warehouse on fire. You see it in news reports, with firefighters, etc.

  • Un incendie dans un immeuble. – A fire in an apartment building.

• un feu = any fire in general:

  • un feu de camp – a campfire
  • un feu de cheminée – a fireplace fire
  • les feux de circulation – traffic lights
  • le feu can also mean “permission to start” (e.g. Donne-moi le feu vert – Give me the green light).

In the sentence, un incendie is chosen because it’s clearly a dangerous, accidental fire in a building, not a cozy or controlled fire.

Commence is the present tense of commencer, so literally:
Un incendie commence... = A fire is starting...

This fits if:

• you are describing something happening right now, or
• you are using the “vivid present” to make a story feel more immediate (like in sports commentary or storytelling).

Other very common alternatives:

• Un incendie s’est déclaré dans un vieux bâtiment...
  → “A fire broke out in an old building...” (standard journalistic phrase in the past tense)

• Un incendie s’est déclaré hier soir...
  → A fire broke out last night...

• Un incendie a commencé dans un vieux bâtiment...
  → Also correct, but s’est déclaré is more idiomatic for fires.

So the present commence is grammatically fine; the choice of tense and verb just depends on whether you are narrating something live, telling a past story, or writing a news headline.

French prepositions for place are quite specific:

• dans = inside / within a space

  • dans un bâtiment – in a building (physically inside)
  • dans la maison, dans la voiture, etc.

• à is not used to mean “inside a building” like English at / in.

  • à is used with cities, towns, some places by name:
    
    • à Paris, à Londres, à l’école (fixed expression), etc.
      Saying à un vieux bâtiment would sound like “at an old building” as an external point, and even then it’s odd here.

• en is used with:

  • many countries/regions: en France, en Europe
  • months/years: en janvier, en 2020
  • some transport: en voiture, en train
    It is not used for “in a building” in this way.

So for a fire physically starting inside the building, dans un vieux bâtiment is the natural choice.

There are two issues: gender and the special forms of vieux.

1. Gender of bâtiment

   • bâtiment is masculine, so the article must be un, not une.
   • Therefore: un bâtiment, not une bâtiment.

2. Forms of vieux (“old”)
   Masculine singular:

   • vieux before a consonant: un vieux bâtiment, un vieux chien
   • vieil before a vowel or mute h: un vieil homme, un vieil immeuble, un vieil ami

   Feminine:

   • vieille: une vieille maison, une vieille voiture

So:

• un vieux bâtiment – correct (masc. + consonant)
• un vieil bâtiment – incorrect (bâtiment starts with b, a consonant)
• une vieille bâtiment – incorrect (wrong gender and wrong adjective form).

Most French adjectives do indeed come after the noun:

• un bâtiment dangereux – a dangerous building
• une voiture rouge – a red car

But a small, very frequent group usually comes before the noun. Often taught as the BAGS / BANGS group:

• Beauty: beau, joli
• Age: vieux, jeune, nouveau
• Goodness: bon, mauvais
• Size: grand, petit, gros

Because vieux is an age adjective, it normally goes before the noun:

• un vieux bâtiment
• une vieille maison
• un jeune homme
• une petite ville

So the word order un vieux bâtiment is exactly what we expect in French.

The key point: the preposition meaning “near” is près de, not just près.

• près de = near
  
  • près de la place – near the square
  • près du parc – near the park
  • près des écoles – near the schools

You always need de after près when it means “near”:

• près de + la = près de la
• près de + le = près du
• près de + les = près des

So près la place is simply ungrammatical in this meaning; it must be près de la place.

Place in French is a flexible word. It can mean:

1. A public square / plaza (open space in a town)

   • la place du village – the village square
   • la place de la mairie – the town-hall square

2. A seat / place to sit

   • J’ai une place au premier rang. – I have a seat in the front row.
   • Cette place est libre ? – Is this seat free?

3. A spot / space in general

   • Il n’y a plus de place dans la voiture. – There is no more room in the car.

In Un incendie commence dans un vieux bâtiment près de la place, the most natural reading is “near the town square” (or the square in a city), not “near the seat.” The context of buildings in a town strongly suggests meaning 1.

Yes, there are several ways to say “near the square,” with slight differences:

• près de la place

  • Neutral and very common: “near / close to the square.”

• à côté de la place

  • Literally “next to / beside the square.”
  • Often suggests being right by the square, a bit closer than just “somewhere nearby.”

• proche de la place

  • Also “near the square.”
  • Slightly more formal / literary in the physical sense; very common for emotional closeness (proche de sa famille).

• non loin de la place

  • “Not far from the square” – a bit more indirect.

All are grammatically fine; près de la place is the most neutral, everyday choice.

No. In French you normally need an article (or another determiner like ce, mon, ceci) before a singular count noun.

So:

• dans un vieux bâtiment – correct
• dans vieux bâtiment – incorrect

The indefinite article un tells us it’s one such building, not some general or abstract idea. Likewise in French you would also keep the article for other nouns:

• près de la place – near the square (not just “near square”)
• dans une vieille maison – in an old house

So the repetition of articles like un and la is normal and required in standard French.