Content type 'multipart/form-data;boundary=----...;charset=UTF-8' not supported

I want to send an object to the controller that has several lists with files and several fields with plain text.

public class ContributionNew<T extends MovieInfoDTO> {    private List<T> elementsToAdd;    private Map<Long, T> elementsToUpdate;    private Set<Long> idsToDelete;    private Set<String> sources;    private String comment;}public class Photo extends MovieInfoDTO {    private MultipartFile photo;}@PostMapping(value = "/{id}/contributions/photos")@ResponseStatus(HttpStatus.CREATED)publicResponseEntity<Void> createPhotoContribution(        @ApiParam(value = "The movie ID", required = true)        @PathVariable("id") final Long id,        @ApiParam(value = "The contribution", required = true)        @RequestBody @Valid final ContributionNew<Photo> contribution) {

I am sending data using postman. However, he throws me away

org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'multipart/form-data;boundary=----WebKitFormBoundarywY7ByvgonAjDoaCT;charset=UTF-8' not supported

What should I set the Content-type for this controller so that I can send an object that has fields of plain text and lists with files?

If I set the header in the header

Content-type: multipart/form-data; charset=utf-8

it throws me in the console

org.apache.tomcat.util.http.fileupload.FileUploadException: the request was rejected because no multipart boundary was found