Il se peut que la caution soit un peu élevée, alors nous voulons relire le bail calmement.

Il se peut que is a common French expression meaning it may be that, it is possible that, or more naturally in English, maybe/perhaps.

So:

• Il se peut que la caution soit un peu élevée
  = The deposit may be a little high

A few useful notes:

• il here does not refer to a person or thing; it is an impersonal it
• se peut comes from se pouvoir, used almost only in this expression
• the whole structure is followed by que
  • a verb in the subjunctive

It is a fairly neutral, standard way to express possibility.

Because Il se peut que normally requires the subjunctive.

The verb être in the subjunctive, third person singular, is soit:

• indicative: elle est
• subjunctive: qu’elle soit

So:

• Il se peut que la caution soit élevée = correct
• Il se peut que la caution est élevée = not correct in standard French

This happens because Il se peut que expresses uncertainty or possibility, and many such expressions trigger the subjunctive.

No. This is a classic false friend.

In this sentence, la caution usually means a deposit, especially a security deposit paid when renting a property.

So:

• la caution = deposit / security deposit
• English caution = prudence / warning, which is something different

Depending on region and context, you may also hear:

• le dépôt de garantie = security deposit

In rental language, la caution is very commonly understood as the money paid as a guarantee.

Because élevée agrees with la caution, which is a feminine singular noun.

French adjectives usually agree in gender and number with the noun they describe:

• masculine singular: élevé
• feminine singular: élevée
• masculine plural: élevés
• feminine plural: élevées

Since la caution is feminine singular, you get:

• la caution soit un peu élevée

Here élevée means high, not literally elevated in the physical sense.

Yes, literally it comes from the idea of being raised, but in French it is very common to use élevé / élevée to mean high in price, amount, level, cost, etc.

Examples:

• un prix élevé = a high price
• des frais élevés = high fees
• une caution élevée = a high deposit

So in this sentence, élevée is a natural way to say the deposit seems expensive or larger than expected.

Un peu means a little or somewhat.

So:

• élevée = high
• un peu élevée = a little high / somewhat high

It softens the statement. Instead of saying the deposit is definitely high in a strong way, it suggests a more moderate judgment.

Compare:

• La caution est élevée. = The deposit is high.
• La caution est un peu élevée. = The deposit is a little high.

Here alors means something like:

• so
• therefore
• in that case
• so then

It links the two ideas:

1. the deposit may be a little high
2. therefore, we want to reread the lease carefully

So the logic is:

• It may be a little high, so we want to reread the lease carefully.

In other contexts, alors can also mean then.

Lire means to read.
Relire means to read again, to reread, or sometimes to review by reading.

So:

• lire le bail = to read the lease
• relire le bail = to reread the lease / go over the lease again

The prefix re- often gives the idea of again:

• faire = do

• refaire = do again

• voir = see

• revoir = see again / review

• lire = read
• relire = reread

Le bail means the lease.

It is a common legal or housing term for a rental agreement.

Related words:

• un bail = a lease
• un contrat de location = a rental contract
• le locataire = the tenant
• le propriétaire = the owner / landlord

So relire le bail means to reread the lease agreement.

Calmement means calmly. In this sentence, it is best understood as:

• carefully
• without rushing
• calmly and thoroughly

So:

• nous voulons relire le bail calmement
  = we want to reread the lease carefully / calmly

Placing it at the end is very natural in French. It modifies the action relire.

French often puts adverbs after the verb or after the object, especially with longer phrases like this.

Yes, in many everyday situations, on veut would sound more conversational.

Compare:

• nous voulons relire le bail calmement = more neutral or slightly more formal
• on veut relire le bail calmement = more natural in everyday spoken French

Both mean we want to reread the lease carefully.

French speakers often use on instead of nous in speech, but nous is still completely correct and common, especially in writing or more careful speech.

It could be. That would also be a natural sentence, but it is structured differently.

For example:

• Peut-être que la caution est un peu élevée.
  = Maybe the deposit is a little high.

With peut-être que, the verb is usually in the indicative:

• est

With il se peut que, the verb goes into the subjunctive:

• soit

So both are possible, but the grammar changes:

• Peut-être que la caution est...
• Il se peut que la caution soit...

Both express possibility, though il se peut que can sound slightly more formal or more carefully phrased.

The sentence follows a very typical French pattern:

• Il se peut que
  • subordinate clause
• then a connector: alors
• then the main clause: nous voulons relire le bail calmement

Broken down:

• Il se peut que = it may be that
• la caution soit un peu élevée = the deposit may be a little high
• alors = so
• nous voulons relire le bail calmement = we want to reread the lease carefully

Nothing unusual is happening, but it is a good example of:

1. an impersonal expression
2. the subjunctive after que
3. adjective agreement
4. natural placement of an adverb at the end of the sentence