diff --git a/CHANGELOG.md b/CHANGELOG.md
index 747a71ea..a02f9d05 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Correct column style even when using rowspan [#1249](https://github.com/PHPOffice/PhpSpreadsheet/pull/1249)
 - Do not confuse defined names and cell refs [#1263](https://github.com/PHPOffice/PhpSpreadsheet/pull/1263)
 - XLSX reader/writer keep decimal for floats with a zero decimal part [#1262](https://github.com/PHPOffice/PhpSpreadsheet/pull/1262)
+- ODS writer prevent invalid numeric value if locale decimal separator is comma [#1268](https://github.com/PHPOffice/PhpSpreadsheet/pull/1268)
 
 ## [1.10.0] - 2019-11-18
 
diff --git a/src/PhpSpreadsheet/Writer/Ods/Content.php b/src/PhpSpreadsheet/Writer/Ods/Content.php
index 962f8fff..dea5100f 100644
--- a/src/PhpSpreadsheet/Writer/Ods/Content.php
+++ b/src/PhpSpreadsheet/Writer/Ods/Content.php
@@ -314,7 +314,7 @@ class Content extends WriterPart
             }
 
             if ($size = $font->getSize()) {
-                $writer->writeAttribute('fo:font-size', sprintf('%.1fpt', $size));
+                $writer->writeAttribute('fo:font-size', sprintf('%.1Fpt', $size));
             }
 
             if ($font->getUnderline() && $font->getUnderline() != Font::UNDERLINE_NONE) {