diff --git a/src/ifc5d/ifc5d/csv2ifc.py b/src/ifc5d/ifc5d/csv2ifc.py
index 2e362d302e..7632b10f44 100644
--- a/src/ifc5d/ifc5d/csv2ifc.py
+++ b/src/ifc5d/ifc5d/csv2ifc.py
@@ -20,6 +20,7 @@ import csv
 import ifcopenshell
 import ifcopenshell.api
 import ifcopenshell.util.unit
+import locale
 
 
 class Csv2Ifc:
@@ -38,7 +39,8 @@ class Csv2Ifc:
     def parse_csv(self):
         self.parents = {}
         self.headers = {}
-        with open(self.csv, "r") as csv_file:
+        locale.setlocale(locale.LC_ALL, "")  # set the system locale
+        with open(self.csv, "r", encoding="ISO-8859-1") as csv_file:
             reader = csv.reader(csv_file)
             for row in reader:
                 if not row[0]:
@@ -67,7 +69,7 @@ class Csv2Ifc:
         unit = row[self.headers["Unit"]]
         if self.has_categories:
             cost_values = {
-                k: float(row[v])
+                k: locale.atof(row[v])
                 for k, v in self.headers.items()
                 if k not in ["Hierarchy", "Identification", "Name", "Quantity", "Unit", "Subtotal"] and row[v]
             }
diff --git a/src/ifc5d/ifc5d/ifc5Dspreadsheet.py b/src/ifc5d/ifc5d/ifc5Dspreadsheet.py
index 7c91934790..546f2bd2c1 100644
--- a/src/ifc5d/ifc5d/ifc5Dspreadsheet.py
+++ b/src/ifc5d/ifc5d/ifc5Dspreadsheet.py
@@ -233,9 +233,8 @@ class Ifc5Dwriter:
                 "Unit",
             ]
             cost_rate_categories = IfcDataGetter.get_cost_rates_categories(cost_schedule)
-            self.sheet_data[sheet_id]["headers"].extend(list(cost_rate_categories)).extend(
-                ["Rate Subtotal", "Total Price", "Children"]
-            )
+            self.sheet_data[sheet_id]["headers"].extend(list(cost_rate_categories))
+            self.sheet_data[sheet_id]["headers"].extend(["Rate Subtotal", "Total Price", "Children"])
             self.sheet_data[sheet_id]["cost_items"] = IfcDataGetter.get_cost_items_data(self.file, cost_schedule)
             self.sheet_data[sheet_id]["UpdateDate"] = IfcDataGetter.canonicalise_time(
                 ifcopenshell.util.date.ifc2datetime(cost_schedule.UpdateDate)