---
title: "Create rent modification details"
method: POST
path: "/leases/{lease_id}/amendments/{amendment_id}/rent-detail"
tags: ["Amendment Rent Details"]
---

# Create rent modification details

`POST /leases/{lease_id}/amendments/{amendment_id}/rent-detail`

## Request

- Base URL: `https://api.faireplace.com/api`
- URL: `https://api.faireplace.com/api/leases/{lease_id}/amendments/{amendment_id}/rent-detail`
- Auth: HTTP bearer

Create the rent detail for a `RENT_MODIFICATION` amendment. Only one rent detail can exist per amendment (1:1 relationship).

**Validation rules:**
- `previous_amount` and `new_amount` must be >= 0
- In **zone tendue**, the new amount is validated against `reference_rent_increased_per_m2 x surface` at activation (Art. 17-2 Loi 89-462 / ALUR)

## Path parameters

- `lease_id` string, uuid, required
- `amendment_id` string, uuid, required

## Request body

- CreateAmendmentRentDetailDto: Data for creating rent modification details
  - `previous_amount` number, required: Previous monthly rent (must be >= 0)
  - `new_amount` number, required: New monthly rent (must be >= 0)
  - `increase_percentage` number, nullable
  - `index_value_id` string, uuid, nullable
  - `increase_cap_id` string, uuid, nullable
  - `calculation_method` 'INDEX_BASED' | 'NEGOTIATED' | 'LEGAL_INCREASE' | 'CAPPED', required
  - `calculation_details` object, nullable

## Response `201`

Rent detail created

- AmendmentRentDetailResponse: Rent modification details for a RENT_MODIFICATION amendment (1:1 relationship)
  - `id` string, uuid, required
  - `amendment_id` string, uuid, required
  - `previous_amount` number, required: Previous monthly rent amount (EUR)
  - `new_amount` number, required: New monthly rent amount (EUR). In zone tendue, must not exceed reference_rent_increased_per_m2 x surface (Art. 17-2 Loi 89-462)
  - `increase_percentage` number, nullable: Percentage increase
  - `index_value_id` string, uuid, nullable: Reference to the rent index value used for calculation
  - `increase_cap_id` string, uuid, nullable: Reference to the rent increase cap applied
  - `calculation_method` 'INDEX_BASED' | 'NEGOTIATED' | 'LEGAL_INCREASE' | 'CAPPED', required: Method used to calculate the new rent
  - `calculation_details` object, nullable: JSON details of the calculation methodology

## Other responses

- `400`: Bad request
- `401`: Unauthorized
- `409`: A rent detail already exists for this amendment
- `422`: Unprocessable Entity

---

[API](https://skmtc.dev/faireplace/apis/faireplace-property-management-api.md) · [All operations](https://skmtc.dev/faireplace/apis/faireplace-property-management-api/llms.txt) · [OpenAPI document](https://skmtc.dev/faireplace/apis/faireplace-property-management-api/revisions/69de39762919?raw)