diff --git a/addons/mail/static/src/models/composer/composer.js b/addons/mail/static/src/models/composer/composer.js
index a712f509630..cfec9805308 100644
--- a/addons/mail/static/src/models/composer/composer.js
+++ b/addons/mail/static/src/models/composer/composer.js
@@ -510,7 +510,7 @@ function factory(dependencies) {
          * @returns {mail.partner[]}
          */
         _computeMentionedPartners() {
-            const inputMentions = this.textInputContent.replace(/\n/g, "\n ").match(
+            const inputMentions = this.textInputContent.replace(/\n/g, " \n ").match(
                 new RegExp("@[^ ]+(?= | |$)", 'g')
             ) || [];
             const unmentionedPartners = [];
@@ -533,7 +533,7 @@ function factory(dependencies) {
          * @returns {mail.partner[]}
          */
         _computeMentionedChannels() {
-            const inputMentions = this.textInputContent.replace('\n', "\n ").match(
+            const inputMentions = this.textInputContent.replace(/\n/g, " \n ").match(
                 new RegExp("#[^ ]+(?= | |$)", 'g')
             ) || [];
             const unmentionedChannels = [];
@@ -580,7 +580,7 @@ function factory(dependencies) {
             if (this.mentionedPartners.length === 0 && this.mentionedChannels.length === 0) {
                 return body;
             }
-            const inputMentions = body.replace(new RegExp('<br/>', 'g'), "<br/> ")
+            const inputMentions = body.replace(new RegExp('<br/>', 'g'), " <br/> ")
                 .match(new RegExp("(@|#)" + '[^ ]+(?= |&nbsp;|$)', 'g'))
                 .filter(match => !match.endsWith("<br/>"));
             const substrings = [];