[ADD] accounting/l10n: new localization for luxembourg

task-id 2780977

closes odoo/documentation#1704

Signed-off-by: Castillo Jonathan (jcs) <jcs@odoo.com>

content/applications/finance/accounting/fiscal_localizations/localizations.rst

@@ -16,6 +16,7 @@ Localizations
    localizations/germany
    localizations/indonesia
    localizations/italy_IT
+   localizations/luxembourg
    localizations/mexico
    localizations/netherlands
    localizations/spain

content/applications/finance/accounting/fiscal_localizations/localizations/luxembourg.rst

@@ -0,0 +1,60 @@
+==========
+Luxembourg
+==========
+
+Standard Chart of Accounts - PCN 2020
+=====================================
+
+Odoo's :doc:`Fiscal Localization Package <../overview/fiscal_localization_packages>` for Luxembourg
+includes the current **Standard Chart of Accounts (PCN 2020)**, effective since January 2020.
+
+eCDF tax return
+===============
+
+Tax returns in Luxembourg require a specific XML file to upload on the eCDF.
+
+To download it, go to :menuselection:`Accounting --> Report --> Audit Reports --> Tax Report`, and
+click on :guilabel:`Export eCDF declaration`.
+
+.. seealso::
+   - :doc:`../../reporting/declarations/tax_returns`
+   - `Platform for electronic gathering of financial data (eCDF) <http://www.ecdf.lu>`_
+
+Annual tax report
+=================
+
+You can generate an XML file to electronically file your annual tax report with the tax office.
+
+To do so, go to :menuselection:`Accounting --> Report --> Luxembourg --> Annual Tax Report`, click
+on :guilabel:`Create`, then define the annual period in the :guilabel:`Year` field.
+
+The **simplified annual declaration** is automatically generated. You can manually add values in all
+the fields to get a **complete annual declaration**.
+
+.. image:: luxembourg/annual-tax-report.png
+   :align: center
+   :alt: Odoo Accounting (Luxembourg localization) generates an annual tax declaration.
+
+Finally, click on :guilabel:`Export XML` to download the XML file.
+
+FAIA (SAF-T)
+============
+
+**FAIA (Fichier d’Audit Informatisé AED)** is a standardized and structured file that facilitates
+the exchange of information between the taxpayers' accounting system and the tax office. It is the
+Luxembourgish version of the OECD-recommended SAF-T (Standard Audit File for Tax).
+
+Odoo can generate an XML file that contains all the content of an accounting period according to the
+rules imposed by the Luxembourg tax authorities on digital audit files.
+
+Configuration
+-------------
+
+:ref:`Install <general/install>` the module :guilabel:`Luxembourg Standard Audit File for Tax`
+(module's technical name: ``l10n_lu_saft``).
+
+Export FAIA file
+----------------
+
+Go to :menuselection:`Accounting --> Reporting --> Audit Reports -->  General Ledger`, then click on
+:guilabel:`Export SAF-T (Luxembourg)`.