# Automatic Default Tax Rule on Product Creation

> What this module does Since PrestaShop 1.7, a newly created product has no tax rule: the Tax rule field in the Pricing tab stays on "No tax" until you change…

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- Last updated: 2026-07-22
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## What this module does

Since PrestaShop 1.7, a newly created product has no tax rule: the **Tax rule** field in the _Pricing_ tab stays on "No tax" until you change it by hand. On an active catalog the oversight happens fast — and a product published without VAT throws off both the tax-inclusive price shown in your shop and your accounting.

This module automatically applies the tax rules group of your choice to **every product created**, with no manual step. An "only fill when empty" mode makes sure an already chosen rule is never overwritten.

## Requirements

- PrestaShop 8.0 to 9.x
- PHP 7.4 to 8.3
- At least one active tax rules group configured under **International > Taxes > Tax Rules**

The module does not create any tax rule. It simply applies a rule that already exists in your shop. If your tax rules list is empty, create one before installing the module.

## Installation

1. Download the ZIP archive from your DataFirefly customer account.
2. In the PrestaShop back office, go to **Modules > Module Manager**.
3. Click **Upload a module** in the top right, then drop the ZIP file.
4. Once installation completes, click **Configure**.

**Important:** until you pick a tax rules group in the configuration, the module deliberately stays inactive. This is a safeguard so it never applies an unwanted rule right after installation.

## Configuration

The configuration page has two settings.

### Tax rules group to assign

A drop-down lists every active tax rules group in your shop (for example "FR TVA 20%"). Pick the one that should be applied by default to new products.

The first entry in the list is **"Do nothing (disabled)"**. Select it if you want to temporarily suspend the module without uninstalling it.

### Override existing value

This switch controls how the module behaves when a product already has a tax rule at creation time.

- **Yes** (default): the configured group is always applied, whatever the existing value.
- **No**: the group is only applied when the product has no tax rule at all. An existing value is never modified.

Set this option to **No** if you regularly duplicate already correctly configured products: copies will then keep the source product's tax rule.

Click **Save** to confirm. The module is active immediately.

## How it works

The module hooks into `actionObjectProductAddAfter`, fired by PrestaShop right after a new product row is inserted into the database. It then writes the `id_tax_rules_group` field into the `product` and `product_shop` tables.

### Compatibility with product page v2

The new PrestaShop 8 product page works differently from the old one: as soon as you click **New product**, PrestaShop immediately creates a temporary product (sometimes called a "ghost product") before you have typed anything at all. That product only shows up in the catalog after the first save.

This is exactly the moment the module steps in. The tax rule is therefore written to the database before the form is even displayed, and the _Pricing_ tab shows the correct group straight away.

**Technical note.** The `actionProductAdd` hook, despite its name, is _not_ fired on normal product creation: the PrestaShop core only calls it when a product is duplicated. That is why this module uses the generic `actionObjectProductAddAfter` hook, which correctly covers every creation path.

### Targeted database write

The module updates only the `id_tax_rules_group` column, through a direct SQL query. It does not call `Product::update()`, which avoids needlessly firing update hooks on a still-empty product. No other product field is touched, and no core override is added.

## Supported creation paths

| Creation method | Rule applied |
| --- | --- |
| Manual creation in the back office (product page v2) | Yes |
| Duplicating an existing product | Yes (can be disabled via the override option) |
| CSV import | Yes |
| Creation through the Webservice / API | Yes |
| Products that already existed before installation | No — the module only acts at creation time |

The module does not retroactively fix products already present in your catalog. For those, use PrestaShop's native bulk edit or a bulk update module.

## Multistore

The `id_tax_rules_group` field is shop-specific. The module therefore writes the value into the `product` table as well as `product_shop`, on the shop scope matching the product's creation context.

The tax rules group chosen in the configuration is, however, shared across the whole installation. If your shops need different tax rules, apply the most common one and adjust exceptions manually.

## Troubleshooting

### The tax rule is not applied to new products

Check in this order:

1. **Is a group actually selected?** Open the module configuration: if the list shows "Do nothing (disabled)", the module is inactive by design. Pick a group and save.
2. **Is the hook properly registered?** If you updated the module from version 1.0.0, the hook it uses has changed. Copying files over is not enough: uninstall then reinstall the module from the Module Manager so PrestaShop registers the new hook.
3. **Is the cache cleared?** Go to **Advanced Parameters > Performance** and clear the cache.
4. **Does the tax rules group still exist?** If the selected group has since been deleted, the module does nothing, as a safeguard. Select another one.

### A duplicated product loses its original tax rule

This is the expected behaviour when **Override existing value** is enabled: the default group is reapplied to the copy. Set the option to **No** so duplicates keep the source product's rule.

### The tax-inclusive price does not update in the form

The tax-inclusive price is computed browser-side from the selected tax rule. Reload the product page: since the rule is correctly stored in the database, the _Pricing_ tab will show the right group and recompute the price.

## Uninstalling

From the **Module Manager**, click **Uninstall**. The module deletes its two configuration keys and unregisters from hooks. This module creates no database table, and tax rules already applied to your products are left untouched.

## Version history

### 1.1.0

- Switched to the `actionObjectProductAddAfter` hook to cover creation through product page v2 (temporary product)
- Confirmed compatibility with PrestaShop 8 and 9

### 1.0.0

- Initial release: automatic tax rules group assignment on creation
- Configurable default group and override mode