diff --git a/data/helpers.d/string b/data/helpers.d/string
index b77b42ef7..adfdf89fe 100644
--- a/data/helpers.d/string
+++ b/data/helpers.d/string
@@ -22,8 +22,19 @@ ynh_string_random() {
 # (see sed manual page for more information)
 ynh_replace_string () {
 	delimit=@
-	match_string=${1//${delimit}/"\\${delimit}"}	# Escape the delimiter if it's in the string.
+
+        # Escape any backslash to preserve them as simple backslash.
+        match_string=${match_string//\\/"\\\\"}
+        replace_string=${replace_string//\\/"\\\\"}
+
+        # Escape the & character, who has a special function in sed.
+        match_string=${match_string//&/"\&"}
+        replace_string=${replace_string//&/"\&"}
+
+	# Escape the delimiter if it's in the string.
+	match_string=${1//${delimit}/"\\${delimit}"}
 	replace_string=${2//${delimit}/"\\${delimit}"}
+
 	workfile=$3
 
 	sudo sed --in-place "s${delimit}${match_string}${delimit}${replace_string}${delimit}g" "$workfile"