curl --request GET \
  --url https://api.leanpay.fr/v1/public/contacts/{contactId} \
  --header 'Authorization: <api-key>'

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "tenantId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "clientId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "title": "<string>",
  "firstName": "<string>",
  "lastName": "<string>",
  "email": "<string>",
  "phoneNumber": "<string>",
  "mobilePhoneNumber": "<string>",
  "externalId": "<string>",
  "main": true,
  "createdAt": "2023-11-07T05:31:56Z",
  "updatedAt": "2023-11-07T05:31:56Z"
}