diff --git a/src/controllers/auth.controller.ts b/src/controllers/auth.controller.ts
index 9ae845f..5b2be59 100644
--- a/src/controllers/auth.controller.ts
+++ b/src/controllers/auth.controller.ts
@@ -1,7 +1,9 @@
 import JwtService from "@services/jwt.service";
 
 import type { IReqEditUserData } from "@interfaces/IReqEditUserData";
+import type { IReqRegister } from "@interfaces/requests/IReqRegister";
 import UserService from "@services/user.service";
+import { isEmail } from "@utils/validators/email";
 import type { Request, Response } from "express";
 import { Logger } from "tslog";
 
@@ -9,21 +11,8 @@ const logger = new Logger({
 	name: "AuthController",
 });
 
-//FIX Better return object interface
-/**
- * Registers a user with the given request data.
- *
- * @param {Request} req - The request object containing user data.
- * @param {Response} res - The response object to send the registration result.
- *
- * @return {Promise} A promise that resolves to the registration result.
- *                   It can have the following properties:
- *                   - error: "gdprNotApproved" if GDPR is not approved
- *                   - error: "exist" if the user already exists
- *                   - Otherwise, the registered user data
- */
 async function registerUser(req: Request, res: Response): Promise<unknown> {
-	const body = req.body;
+	const body: IReqRegister = req.body;
 	if (!body) {
 		logger.warn(`Invalid input data (${req.ip})`);
 		return res.type("application/json").status(400).json({
@@ -35,7 +24,7 @@ async function registerUser(req: Request, res: Response): Promise<unknown> {
 		!body.username ||
 		!body.firstName ||
 		!body.lastName ||
-		!body.displayName
+		!body.email
 	) {
 		logger.warn(`Field(s) missing (${req.ip})`);
 		return res.type("application/json").status(400).json({
@@ -43,13 +32,20 @@ async function registerUser(req: Request, res: Response): Promise<unknown> {
 		});
 	}
 
+	if (!isEmail(body.email)) {
+		logger.warn(`Invalid email format (${req.ip})`);
+		return res.type("application/json").status(400).json({
+			error: "Invalid email format",
+		});
+	}
+
 	let gdpr = false;
 	if (body.gdpr === true) {
 		gdpr = true;
 	}
-	const sanitizeData = {
+	const sanitizeData: IReqRegister = {
 		username: `${body.username}`,
-		displayName: `${body.displayName}`,
+		email: `${body.email.toLowerCase()}`,
 		gdpr: gdpr,
 		password: `${body.password}`,
 		firstName: `${body.firstName}`,
@@ -74,7 +70,7 @@ async function registerUser(req: Request, res: Response): Promise<unknown> {
 	}
 
 	// SUCCESS
-	logger.info(`User registered successfully (${req.ip})`);
+	logger.info(`User registered successfully (${sanitizeData.username})`);
 	return res.type("application/json").status(201).json(RegisterServiceResult);
 }