diff --git a/Misc/NEWS.d/next/Library/2019-01-02-20-04-49.bpo-35643.DaMiaV.rst b/Misc/NEWS.d/next/Library/2019-01-02-20-04-49.bpo-35643.DaMiaV.rst
new file mode 100644
index 0000000..0b47bb6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-01-02-20-04-49.bpo-35643.DaMiaV.rst
@@ -0,0 +1,2 @@
+Fixed a SyntaxWarning: invalid escape sequence in Modules/_sha3/cleanup.py.
+Patch by Mickaël Schoentgen.
diff --git a/Modules/_sha3/cleanup.py b/Modules/_sha3/cleanup.py
index 17c56b3..4f53681 100755
--- a/Modules/_sha3/cleanup.py
+++ b/Modules/_sha3/cleanup.py
@@ -8,7 +8,7 @@
 import re
 
 CPP1 = re.compile("^//(.*)")
-CPP2 = re.compile("\ //(.*)")
+CPP2 = re.compile(r"\ //(.*)")
 
 STATICS = ("void ", "int ", "HashReturn ",
            "const UINT64 ", "UINT16 ", "    int prefix##")