diff --git a/Blazor/Blazor/Models/AdministratorModel.cs b/Blazor/Blazor/Models/AdministratorModel.cs
index 89e5042..91d1dd6 100644
--- a/Blazor/Blazor/Models/AdministratorModel.cs
+++ b/Blazor/Blazor/Models/AdministratorModel.cs
@@ -1,6 +1,7 @@
 using Microsoft.AspNetCore.Cryptography.KeyDerivation;
 using Microsoft.AspNetCore.Identity;
 using System.Security.Cryptography;
+using System.ComponentModel.DataAnnotations;
 using System.Text;
 
 namespace Blazor.Models;
@@ -8,7 +9,14 @@ namespace Blazor.Models;
 public class AdministratorModel 
 {
     public int Id { get; set; }
+
+    [Required(ErrorMessage = "Username is required")]
+    [StringLength(50, ErrorMessage = "Username is too long.")]
     public string Username { get; set; }
+
+    [Required(ErrorMessage = "Password is required")]
+    [RegularExpression(@"^[^\s]+$", ErrorMessage = "Le champ ne doit pas contenir d'espaces.")]
+    [StringLength(255, ErrorMessage = "{0} length must be between {2} and {1}.", MinimumLength = 6)]
     public string HashedPassword { get; set; }
 
     public void HashPassword(string password)
diff --git a/Blazor/Blazor/Models/AnswerModel.cs b/Blazor/Blazor/Models/AnswerModel.cs
index ec2d19c..88753e9 100644
--- a/Blazor/Blazor/Models/AnswerModel.cs
+++ b/Blazor/Blazor/Models/AnswerModel.cs
@@ -1,9 +1,14 @@
-namespace Blazor.Models;
+using System.ComponentModel.DataAnnotations;
+
+namespace Blazor.Models;
 
 public class AnswerModel
 
 {
     public int Id { get; set; }
+
+    [Required(ErrorMessage = "Content is required")]
+    [StringLength(40, ErrorMessage = "Content is too long.")]
     public string? Content { get; set; }
     public int? IdQuestion { get; set; }
     public AnswerModel(int id)
diff --git a/Blazor/Blazor/Models/PlayerModel.cs b/Blazor/Blazor/Models/PlayerModel.cs
index 43c37a0..a8da40a 100644
--- a/Blazor/Blazor/Models/PlayerModel.cs
+++ b/Blazor/Blazor/Models/PlayerModel.cs
@@ -1,4 +1,5 @@
 using Microsoft.AspNetCore.Cryptography.KeyDerivation;
+using System.ComponentModel.DataAnnotations;
 using System.Security.Cryptography;
 using System.Text;
 
@@ -7,7 +8,14 @@ namespace Blazor.Models;
 public class PlayerModel
 {
     public int Id { get; set; }
+
+    [Required(ErrorMessage = "Nickname is required")]
+    [StringLength(50, ErrorMessage = "Nickname is too long.")]
     public string Nickname { get; set; }
+
+    [Required(ErrorMessage = "Password is required")]
+    [RegularExpression(@"^[^\s]+$", ErrorMessage = "Le champ ne doit pas contenir d'espaces.")]
+    [StringLength(255, ErrorMessage = "{0} length must be between {2} and {1}.", MinimumLength = 6)]
     public string HashedPassword { get; set; }
 
     public void HashPassword(string password)
diff --git a/Blazor/Blazor/Models/QuestionModel.cs b/Blazor/Blazor/Models/QuestionModel.cs
index 4089498..2c1e606 100644
--- a/Blazor/Blazor/Models/QuestionModel.cs
+++ b/Blazor/Blazor/Models/QuestionModel.cs
@@ -1,9 +1,15 @@
 namespace Blazor.Models;
+using System.ComponentModel.DataAnnotations;
 
 public class QuestionModel
 {
     public int Id { get; set; }
+
+    [Required(ErrorMessage = "Content is required")]
+    [StringLength(50, ErrorMessage = "Content is too long.")]
     public string Content { get; set; }
+
+    [Required(ErrorMessage = "Chapter is required")]
     public int IdChapter { get; set; }
     public int IdAnswerGood { get; set; }
     public int Difficulty { get; set; }