diff --git a/js/src/mixins/identityEdition.ts b/js/src/mixins/identityEdition.ts
new file mode 100644
index 000000000..d4f54f862
--- /dev/null
+++ b/js/src/mixins/identityEdition.ts
@@ -0,0 +1,35 @@
+import { Component, Mixins, Vue } from 'vue-property-decorator';
+import { Person } from '@/types/actor';
+
+@Component
+export default class IdentityEditionMixin extends Mixins(Vue) {
+
+  identity = new Person();
+  oldDisplayName: string | null = null;
+
+  autoUpdateUsername(newDisplayName: string | null) {
+    const oldUsername = IdentityEditionMixin.convertToUsername(this.oldDisplayName);
+
+    if (this.identity.preferredUsername === oldUsername) {
+      this.identity.preferredUsername = IdentityEditionMixin.convertToUsername(newDisplayName);
+    }
+
+    this.oldDisplayName = newDisplayName;
+  }
+
+  private static convertToUsername(value: string | null) {
+    if (!value) return '';
+
+        // https://stackoverflow.com/a/37511463
+    return value.toLocaleLowerCase()
+            .normalize('NFD')
+            .replace(/[\u0300-\u036f]/g, '')
+            .replace(/ /g, '_')
+            .replace(/[^a-z0-9_]/g, '')
+            ;
+  }
+
+  validateUsername() {
+    return this.identity.preferredUsername === IdentityEditionMixin.convertToUsername(this.identity.preferredUsername);
+  }
+}
diff --git a/js/src/views/Account/Register.vue b/js/src/views/Account/Register.vue
index d4b23a775..468d9c262 100644
--- a/js/src/views/Account/Register.vue
+++ b/js/src/views/Account/Register.vue
@@ -9,6 +9,10 @@
           {{ $t('To achieve your registration, please create a first identity profile.')}}
         </b-message>
         <form v-if="!validationSent" @submit.prevent="submit">
+          <b-field :label="$t('Display name')">
+            <b-input aria-required="true" required v-model="identity.name" @input="autoUpdateUsername($event)"/>
+          </b-field>
+
           <b-field
             :label="$t('Username')"
             :type="errors.preferred_username ? 'is-danger' : null"
@@ -19,7 +23,7 @@
                 aria-required="true"
                 required
                 expanded
-                v-model="person.preferredUsername"
+                v-model="identity.preferredUsername"
               />
               <p class="control">
                 <span class="button is-static">@{{ host }}</span>
@@ -27,12 +31,8 @@
             </b-field>
           </b-field>
 
-          <b-field :label="$t('Displayed name')">
-            <b-input v-model="person.name"/>
-          </b-field>
-
           <b-field :label="$t('Description')">
-            <b-input type="textarea" v-model="person.summary"/>
+            <b-input type="textarea" v-model="identity.summary"/>
           </b-field>
 
           <p class="control has-text-centered">
@@ -45,7 +45,7 @@
         <div v-if="validationSent && !userAlreadyActivated">
           <b-message title="Success" type="is-success" closable="false">
             <h2 class="title">
-              {{ $t('Your account is nearly ready, {username}', { username: person.preferredUsername }) }}
+              {{ $t('Your account is nearly ready, {username}', { username: identity.preferredUsername }) }}
             </h2>
             <p>
               {{ $t('A validation email was sent to {email}', { email }) }}
@@ -61,22 +61,22 @@
 </template>
 
 <script lang="ts">
-import { Component, Prop, Vue } from 'vue-property-decorator';
-import { IPerson, Person } from '@/types/actor';
+import { Component, Prop } from 'vue-property-decorator';
+import { IPerson } from '@/types/actor';
 import { IDENTITIES, REGISTER_PERSON } from '@/graphql/actor';
 import { MOBILIZON_INSTANCE_HOST } from '@/api/_entrypoint';
 import { RouteName } from '@/router';
 import { changeIdentity } from '@/utils/auth';
-import { ICurrentUser } from '@/types/current-user.model';
+import { mixins } from 'vue-class-component';
+import identityEditionMixin from '@/mixins/identityEdition';
 
 @Component
-export default class Register extends Vue {
+export default class Register extends mixins(identityEditionMixin) {
   @Prop({ type: String, required: true }) email!: string;
   @Prop({ type: Boolean, required: false, default: false }) userAlreadyActivated!: boolean;
 
   host?: string = MOBILIZON_INSTANCE_HOST;
 
-  person: IPerson = new Person();
   errors: object = {};
   validationSent: boolean = false;
   sendingValidation: boolean = false;
@@ -94,7 +94,7 @@ export default class Register extends Vue {
       this.errors = {};
       const { data } = await this.$apollo.mutate<{ registerPerson: IPerson }>({
         mutation: REGISTER_PERSON,
-        variables: Object.assign({ email: this.email }, this.person),
+        variables: Object.assign({ email: this.email }, this.identity),
         update: (store, { data }) => {
           if (this.userAlreadyActivated) {
             const identitiesData = store.readQuery<{ identities: IPerson[] }>({ query: IDENTITIES });
diff --git a/js/src/views/Account/children/EditIdentity.vue b/js/src/views/Account/children/EditIdentity.vue
index 34052b0b7..2bb8df295 100644
--- a/js/src/views/Account/children/EditIdentity.vue
+++ b/js/src/views/Account/children/EditIdentity.vue
@@ -7,13 +7,13 @@
 
     <picture-upload v-model="avatarFile" class="picture-upload"></picture-upload>
 
-    <b-field :label="$t('Display name')">
+    <b-field horizontal :label="$t('Display name')">
       <b-input aria-required="true" required v-model="identity.name" @input="autoUpdateUsername($event)"/>
     </b-field>
 
-    <b-field :label="$t('Username')">
-      <b-field>
-        <b-input aria-required="true" required v-model="identity.preferredUsername" :disabled="isUpdate"/>
+    <b-field horizontal custom-class="username-field" expanded :label="$t('Username')" :message="message">
+      <b-field expanded>
+        <b-input aria-required="true" required v-model="identity.preferredUsername" :disabled="isUpdate" :use-html5-validation="!isUpdate" pattern="[a-z0-9_]+"/>
 
         <p class="control">
           <span class="button is-static">@{{ getInstanceHost() }}</span>
@@ -21,7 +21,7 @@
       </b-field>
     </b-field>
 
-    <b-field :label="$t('Description')">
+    <b-field horizontal :label="$t('Description')">
       <b-input type="textarea" aria-required="false" v-model="identity.summary"/>
     </b-field>
 
@@ -77,10 +77,14 @@
     cursor: pointer;
     margin-top: 15px;
   }
+
+  .username-field + .field {
+    margin-bottom: 0;
+  }
 </style>
 
 <script lang="ts">
-import { Component, Prop, Vue, Watch } from 'vue-property-decorator';
+import { Component, Prop, Watch } from 'vue-property-decorator';
 import {
   CREATE_PERSON,
   CURRENT_ACTOR_CLIENT,
@@ -96,6 +100,8 @@ import { Dialog } from 'buefy/dist/components/dialog';
 import { RouteName } from '@/router';
 import { buildFileFromIPicture, buildFileVariable, readFileAsync } from '@/utils/image';
 import { changeIdentity } from '@/utils/auth';
+import { mixins } from 'vue-class-component';
+import identityEditionMixin from '@/mixins/identityEdition';
 
 @Component({
   components: {
@@ -108,18 +114,21 @@ import { changeIdentity } from '@/utils/auth';
     },
   },
 })
-export default class EditIdentity extends Vue {
+export default class EditIdentity extends mixins(identityEditionMixin) {
   @Prop({ type: Boolean }) isUpdate!: boolean;
 
   errors: string[] = [];
 
   identityName!: string | undefined;
   avatarFile: File | null = null;
-  identity = new Person();
 
-  private oldDisplayName: string | null = null;
   private currentActor: IPerson | null = null;
 
+  get message() {
+    if (this.isUpdate) return null;
+    return this.$t('Only alphanumeric characters and underscores are supported.');
+  }
+
   @Watch('isUpdate')
   async isUpdateChanged () {
     this.resetFields();
@@ -153,16 +162,6 @@ export default class EditIdentity extends Vue {
     return this.createIdentity();
   }
 
-  autoUpdateUsername(newDisplayName: string | null) {
-    const oldUsername = this.convertToUsername(this.oldDisplayName);
-
-    if (this.identity.preferredUsername === oldUsername) {
-      this.identity.preferredUsername = this.convertToUsername(newDisplayName);
-    }
-
-    this.oldDisplayName = newDisplayName;
-  }
-
   /**
    * Delete an identity
    */
@@ -309,18 +308,6 @@ export default class EditIdentity extends Vue {
     }
   }
 
-  private convertToUsername(value: string | null) {
-    if (!value) return '';
-
-    // https://stackoverflow.com/a/37511463
-    return value.toLocaleLowerCase()
-                .normalize('NFD')
-                .replace(/[\u0300-\u036f]/g, '')
-                .replace(/ /g, '_')
-                .replace(/[^a-z0-9._]/g, '')
-    ;
-  }
-
   private async buildVariables() {
     const avatarObj = buildFileVariable(this.avatarFile, 'avatar', `${this.identity.preferredUsername}'s avatar`);
     const res = Object.assign({}, this.identity, avatarObj);