diff --git a/addons/l10n_fr_pos_cert/models/pos.py b/addons/l10n_fr_pos_cert/models/pos.py
index 8f53c3dd1ef..4e4b6f2d61e 100644
--- a/addons/l10n_fr_pos_cert/models/pos.py
+++ b/addons/l10n_fr_pos_cert/models/pos.py
@@ -120,6 +120,12 @@ class pos_order(models.Model):
                 res |= super(pos_order, order).write(vals_hashing)
         return res
 
+    def unlink(self):
+        for order in self:
+            if order.company_id._is_accounting_unalterable():
+                raise UserError(_("According to French law, you cannot delet a point of sale order."))
+        return super(pos_order, self).unlink()
+
 
 class PosOrderLine(models.Model):
     _inherit = "pos.order.line"
diff --git a/addons/l10n_fr_pos_cert/static/src/js/pos.js b/addons/l10n_fr_pos_cert/static/src/js/pos.js
index 8634181937d..20f15e17c0a 100644
--- a/addons/l10n_fr_pos_cert/static/src/js/pos.js
+++ b/addons/l10n_fr_pos_cert/static/src/js/pos.js
@@ -5,12 +5,28 @@ var models = require('point_of_sale.models');
 var screens = require('point_of_sale.screens');
 var rpc = require('web.rpc');
 var session = require('web.session');
+var core = require('web.core');
+var utils = require('web.utils');
 
+var _t = core._t;
+var round_di = utils.round_decimals;
+
+var _super_posmodel = models.PosModel.prototype;
 models.PosModel = models.PosModel.extend({
     is_french_country: function(){
       var french_countries = ['FR', 'MF', 'MQ', 'NC', 'PF', 'RE', 'GF', 'GP', 'TF'];
       return _.contains(french_countries, this.company.country.code);
-    }
+    },
+    delete_current_order: function () {
+        if (this.is_french_country() && this.get_order().get_orderlines().length) {
+            this.gui.show_popup("error", {
+                'title': _t("Fiscal Data Module error"),
+                'body':  _t("Deleting of orders is not allowed."),
+            });
+        } else {
+            _super_posmodel.delete_current_order.apply(this, arguments);
+        }
+    },
 });
 
 
@@ -39,6 +55,62 @@ models.Order = models.Order.extend({
     }
 });
 
+var orderline_super = models.Orderline.prototype;
+models.Orderline = models.Orderline.extend({
+    set_quantity: function (quantity, keep_price) {
+        var current_quantity = this.get_quantity();
+        var new_quantity = parseFloat(quantity) || 0;
+        if (this.pos.is_french_country() && (new_quantity === 0 || new_quantity < current_quantity)) {
+            var quantity_to_decrease = current_quantity - new_quantity;
+            this.pos.gui.show_popup("number", {
+                'title': _t("Decrease the quantity by"),
+                'confirm': function (qty_decrease) {
+                    if (qty_decrease) {
+                        var order = this.pos.get_order();
+                        var selected_orderline = order.get_selected_orderline();
+                        qty_decrease = parseFloat(qty_decrease);
+                        var decimals = this.pos.dp['Product Unit of Measure'];
+                        qty_decrease = round_di(qty_decrease, decimals);
+
+                        var current_total_quantity_remaining = selected_orderline.get_quantity();
+                        order.get_orderlines().forEach(function (orderline, index, array) {
+                            if (selected_orderline.id != orderline.id &&
+                                selected_orderline.get_product().id === orderline.get_product().id &&
+                                selected_orderline.get_discount() === orderline.get_discount()) {
+                                current_total_quantity_remaining += orderline.get_quantity();
+                            }
+                        });
+
+                        if (qty_decrease > current_total_quantity_remaining) {
+                          this.pos.gui.show_popup("error", {
+                              'title': _t("Order error"),
+                              'body':  _t("Not allowed to take back more than was ordered."),
+                          });
+                        } else {
+                            var decrease_line = selected_orderline.clone();
+                            decrease_line.order = order;
+                            orderline_super.set_quantity.apply(decrease_line, [-qty_decrease]);
+                            order.add_orderline(decrease_line);
+                        }
+                    }
+                }
+            });
+        } else {
+            orderline_super.set_quantity.apply(this, arguments);
+        }
+    },
+    can_be_merged_with: function(orderline) {
+            var order = this.pos.get_order();
+            var last_id = Object.keys(order.orderlines._byId)[Object.keys(order.orderlines._byId).length-1];
+
+            if(this.pos.is_french_country() && (order.orderlines._byId[last_id].product.id !== orderline.product.id || order.orderlines._byId[last_id].quantity < 0)) {
+                return false;
+            } else {
+                return orderline_super.can_be_merged_with.apply(this, arguments);
+            }
+        }
+});
+
 
 screens.PaymentScreenWidget.include({
     post_push_order_resolve: function (order, server_ids) {
@@ -70,4 +142,55 @@ screens.PaymentScreenWidget.include({
         }
     },
 });
+
+screens.ProductScreenWidget.include({
+    _onKeypadKeyDown: function (event) {
+        if (this.pos.is_french_country()) {
+            var order = this.pos.get_order();
+            var orderline = this.pos.get_order().selected_orderline;
+            var last_id = Object.keys(order.orderlines._byId)[Object.keys(order.orderlines._byId).length-1];
+
+             if( !orderline || (last_id === orderline.cid && orderline.quantity > 0)){
+                this._super(event);
+            }
+        } else {
+            this._super(event);
+        }
+        },
+   });
+
+screens.NumpadWidget.include({
+    start: function(event) {
+        this._super(event);
+        if (this.pos.is_french_country()) {
+            this.$el.find('.numpad-minus').prop("disabled",true);
+        }
+    },
+    clickChangeMode: function (event) {
+        if (this.pos.is_french_country() && event.currentTarget.attributes['data-mode'].nodeValue === "price") {
+            this.gui.show_popup("error", {
+               'title': _t("Module error"),
+               'body':  _t("Adjusting the price is not allowed."),
+            });
+        } else {
+           this._super(event);
+        }
+    },
+    clickAppendNewChar: function(event) {
+        if (this.pos.is_french_country()) {
+            var order = this.pos.get_order();
+            var orderline = this.pos.get_order().selected_orderline;
+            var last_id = Object.keys(order.orderlines._byId)[Object.keys(order.orderlines._byId).length-1];
+
+            if(last_id === orderline.cid && orderline.quantity > 0){
+                this._super(event);
+            }
+        } else {
+            this._super(event);
+        }
+    },
+});
+
+
+
 });