diff --git a/api/src/controllers/files.ts b/api/src/controllers/files.ts
index 521a78d075..64fd73bf15 100644
--- a/api/src/controllers/files.ts
+++ b/api/src/controllers/files.ts
@@ -4,7 +4,7 @@ import express from 'express';
 import Joi from 'joi';
 import path from 'path';
 import env from '../env';
-import { ForbiddenException, InvalidPayloadException } from '../exceptions';
+import { ForbiddenException, InvalidPayloadException, UnsupportedMediaTypeException } from '../exceptions';
 import { respond } from '../middleware/respond';
 import useCollection from '../middleware/use-collection';
 import { validateBatch } from '../middleware/validate-batch';
@@ -18,7 +18,8 @@ const router = express.Router();
 router.use(useCollection('directus_files'));
 
 const multipartHandler = asyncHandler(async (req, res, next) => {
-	if (req.is('multipart/form-data') === false) return next();
+	if (req.is('multipart/form-data') === false)
+		throw new UnsupportedMediaTypeException(`Unsupported Content-Type header`);
 
 	let headers: BusboyHeaders;
 
diff --git a/api/src/controllers/utils.ts b/api/src/controllers/utils.ts
index d87e5269e3..d1e8bb5848 100644
--- a/api/src/controllers/utils.ts
+++ b/api/src/controllers/utils.ts
@@ -2,7 +2,12 @@ import argon2 from 'argon2';
 import { Router } from 'express';
 import Joi from 'joi';
 import { nanoid } from 'nanoid';
-import { ForbiddenException, InvalidPayloadException, InvalidQueryException } from '../exceptions';
+import {
+	ForbiddenException,
+	InvalidPayloadException,
+	InvalidQueryException,
+	UnsupportedMediaTypeException,
+} from '../exceptions';
 import collectionExists from '../middleware/collection-exists';
 import { respond } from '../middleware/respond';
 import { RevisionsService, UtilsService, ImportService } from '../services';
@@ -94,6 +99,9 @@ router.post(
 	'/import/:collection',
 	collectionExists,
 	asyncHandler(async (req, res, next) => {
+		if (req.is('multipart/form-data') === false)
+			throw new UnsupportedMediaTypeException(`Unsupported Content-Type header`);
+
 		const service = new ImportService({
 			accountability: req.accountability,
 			schema: req.schema,
diff --git a/api/src/exceptions/index.ts b/api/src/exceptions/index.ts
index 3e48408054..2e3c445c0b 100644
--- a/api/src/exceptions/index.ts
+++ b/api/src/exceptions/index.ts
@@ -14,5 +14,6 @@ export * from './range-not-satisfiable';
 export * from './route-not-found';
 export * from './service-unavailable';
 export * from './unprocessable-entity';
+export * from './unsupported-media-type';
 export * from './user-suspended';
 export * from './unexpected-response';
diff --git a/api/src/exceptions/unsupported-media-type.ts b/api/src/exceptions/unsupported-media-type.ts
new file mode 100644
index 0000000000..26031cb96f
--- /dev/null
+++ b/api/src/exceptions/unsupported-media-type.ts
@@ -0,0 +1,7 @@
+import { BaseException } from '@directus/shared/exceptions';
+
+export class UnsupportedMediaTypeException extends BaseException {
+	constructor(message: string, extensions?: Record<string, unknown>) {
+		super(message, 415, 'UNSUPPORTED_MEDIA_TYPE', extensions);
+	}
+}
diff --git a/api/src/services/import.ts b/api/src/services/import.ts
index 6833265cdb..c0d5a9bfd9 100644
--- a/api/src/services/import.ts
+++ b/api/src/services/import.ts
@@ -2,7 +2,7 @@ import { Knex } from 'knex';
 import getDatabase from '../database';
 import { AbstractServiceOptions, SchemaOverview } from '../types';
 import { Accountability } from '@directus/shared/types';
-import { ForbiddenException, InvalidPayloadException } from '../exceptions';
+import { ForbiddenException, InvalidPayloadException, UnsupportedMediaTypeException } from '../exceptions';
 import StreamArray from 'stream-json/streamers/StreamArray';
 import { ItemsService } from './items';
 import { queue } from 'async';
@@ -42,7 +42,7 @@ export class ImportService {
 			case 'text/csv':
 				return await this.importCSV(collection, stream);
 			default:
-				throw new InvalidPayloadException(`Can't import files of type "${mimetype}"`);
+				throw new UnsupportedMediaTypeException(`Can't import files of type "${mimetype}"`);
 		}
 	}
 
diff --git a/docs/reference/introduction.md b/docs/reference/introduction.md
index 8624988c27..803635134c 100644
--- a/docs/reference/introduction.md
+++ b/docs/reference/introduction.md
@@ -261,19 +261,20 @@ and system data. The only difference in the two endpoints are the root query and
 
 Below are the global error codes used within Directus, and what they mean.
 
-| Error Code             | HTTP Status | Description                                                  |
-| ---------------------- | ----------- | ------------------------------------------------------------ |
-| `FAILED_VALIDATION`    | 400         | Validation for this particular item failed                   |
-| `FORBIDDEN`            | 403         | You are not allowed to do the current action                 |
-| `INVALID_CREDENTIALS`  | 401         | Username / password or access token is wrong                 |
-| `INVALID_IP`           | 401         | Your IP address isn't allow-listed to be used with this user |
-| `INVALID_OTP`          | 401         | Wrong OTP was provided                                       |
-| `INVALID_PAYLOAD`      | 400         | Provided payload is invalid                                  |
-| `INVALID_QUERY`        | 400         | The requested query parameters can not be used               |
-| `REQUESTS_EXCEEDED`    | 429         | Hit the rate limit                                           |
-| `ROUTE_NOT_FOUND`      | 404         | Endpoint does not exist                                      |
-| `SERVICE_UNAVAILABLE`  | 503         | Could not use external service                               |
-| `UNPROCESSABLE_ENTITY` | 422         | You tried doing something illegal                            |
+| Error Code               | HTTP Status | Description                                                     |
+| ------------------------ | ----------- | --------------------------------------------------------------- |
+| `FAILED_VALIDATION`      | 400         | Validation for this particular item failed                      |
+| `FORBIDDEN`              | 403         | You are not allowed to do the current action                    |
+| `INVALID_CREDENTIALS`    | 401         | Username / password or access token is wrong                    |
+| `INVALID_IP`             | 401         | Your IP address isn't allow-listed to be used with this user    |
+| `INVALID_OTP`            | 401         | Wrong OTP was provided                                          |
+| `INVALID_PAYLOAD`        | 400         | Provided payload is invalid                                     |
+| `INVALID_QUERY`          | 400         | The requested query parameters can not be used                  |
+| `UNSUPPORTED_MEDIA_TYPE` | 415         | Provided payload format or `Content-Type` header is unsupported |
+| `REQUESTS_EXCEEDED`      | 429         | Hit the rate limit                                              |
+| `ROUTE_NOT_FOUND`        | 404         | Endpoint does not exist                                         |
+| `SERVICE_UNAVAILABLE`    | 503         | Could not use external service                                  |
+| `UNPROCESSABLE_ENTITY`   | 422         | You tried doing something illegal                               |
 
 ::: warning Security