diff --git a/app/models/user.rb b/app/models/user.rb
index a1aa86f..3a2502a 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -23,5 +23,6 @@ class User < ApplicationRecord
   normalizes :email_address, with: ->(e) { e.strip.downcase }
 
   validates :username, presence: true, uniqueness: true
+  validates :email_address, presence: true, uniqueness: true
   validates :lang, inclusion: { in: Languages::AVAILABLE_LANGUAGES.map { |lang| lang[:id] } }
 end
diff --git a/app/views/sessions/new.html.slim b/app/views/sessions/new.html.slim
index 4eabada..60df024 100644
--- a/app/views/sessions/new.html.slim
+++ b/app/views/sessions/new.html.slim
@@ -4,10 +4,12 @@
       .form-floating
         = form.email_field :email_address, autocomplete: "username", required: true, autofocus: true, class: "form-control"
         = form.label :email_address, class: "required"
+          = t("activerecord.attributes.session.email_address")
   .row.mb-3
     .col
       .form-floating
         = form.password_field :password, autocomplete: "current-password", required: true, autofocus: true, class: "form-control", maxlength: 72
         = form.label :password, class: "required"
+          = t("activerecord.attributes.session.password")
 
-  = form.submit "Sign in"
\ No newline at end of file
+  = form.submit t("helpers.buttons.sign_in")
\ No newline at end of file
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 007b480..85674cf 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -68,11 +68,14 @@ en:
         brand: "Brand"
         image: "Image"
         name: "Name"
+      session:
+        email_address: Email address
+        password: Password
       user:
-        username: "Username"
-        email_address: "Email address"
-        lang: "Language"
-        password: "New password"
+        username: Username
+        email_address: Email address
+        lang: Language
+        password: New password
     errors:
       models:
         completion:
@@ -100,6 +103,12 @@ en:
           attributes:
             name:
               blank: The puzzle name cannot be empty
+        user:
+          attributes:
+            email_address:
+              blank: Your email cannot be empty
+            username:
+              blank: Your username cannot be empty
   completions:
     edit:
       title: "Edit completion"
@@ -160,6 +169,7 @@ en:
       edit: "Edit"
       import: CSV Import
       open: Open
+      sign_in: Sign in
       save: Save
     field: Field
     none: No field selected
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 452b26b..6d56c77 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -39,11 +39,14 @@ fr:
         brand: "Marque"
         image: "Image"
         name: "Nom"
+      session:
+        email_address: Adresse email
+        password: Mot de passe
       user:
-        username: "Nom d'utilisateur.ice"
-        email_address: "Adresse email"
-        lang: "Langue de l'interface"
-        password: "Nouveau mot de passe"
+        username: Nom d'utilisateur.ice
+        email_address: Adresse email
+        lang: Langue de l'interface
+        password: Nouveau mot de passe
     errors:
       models:
         completion:
@@ -71,6 +74,12 @@ fr:
           attributes:
             name:
               blank: Le nom du puzzle est obligatoire
+        user:
+          attributes:
+            email_address:
+              blank: L'email est obligatoire
+            username:
+              blank: Le nom d'utilisateur.ice est obligatoire
   completions:
     edit:
       title: "Modifier la complétion"
@@ -131,6 +140,7 @@ fr:
       edit: "Modifier"
       import: Importer un CSV
       open: Détails
+      sign_in: Se connecter
       save: Modifier
     field: Champ
     none: Aucun champ sélectionné