A simple example showing how doctrine behaviors (in this chase soft-deleteable) can be used within TYPO3 Flow.

composer.json

{
    ...
    "require": {
        "typo3/flow": "2.0.*",
        "gedmo/doctrine-extensions": "2.3.*"
    },
    ...
}

Settings.yaml

TYPO3:
  Flow:
     # disable reflection for non psr-0 compliant 3rd party packages
    object:
      excludeClasses:
       'gedmo.doctrineextensions' : ['Gedmo\\.*']

     # register soft deletable filter & event listeners
    persistence:
      doctrine:
        filters:
          soft-deletable: 'Gedmo\SoftDeleteable\Filter\SoftDeleteableFilter'
        eventListeners:
          -
            events: ['onFlush', 'loadClassMetadata']
            listener: 'Gedmo\SoftDeleteable\SoftDeleteableListener'

SoftDeletableTrait.php

<?php
namespace Your\Package\Domain\Model;

use TYPO3\Flow\Annotations as Flow;
use Doctrine\ORM\Mapping as ORM;
use Gedmo\Mapping\Annotation as Gedmo;

/**
 * Trait for soft-deletable entities.
 * Usage:
 *
 *  * Add @Gedmo\SoftDeleteable(fieldName="deletedAt") annotation to your entity
 *  * add "use SoftDeletableTrait;" to your entity
 */
trait SoftDeletableTrait {

	/**
	 * DateTime when this entity was deleted (used for "Soft-Delete behaviour")
	 *
	 * @var \DateTime
	 * @ORM\Column(nullable=true)
	 */
	protected $deletedAt;

	/**
	 * @return \DateTime
	 */
	public function getDeletedAt() {
		return $this->deletedAt;
	}

	/**
	 * @param \DateTime $deletedAt
	 * @return void
	 */
	public function setDeletedAt(\DateTime $deletedAt) {
		$this->deletedAt = $deletedAt;
	}
}

SomeEntity.php

<?php
namespace Your\Package\Domain\Model;

use TYPO3\Flow\Annotations as Flow;
use Doctrine\ORM\Mapping as ORM;
use Gedmo\Mapping\Annotation as Gedmo;

/**
 * Some Entity
 *
 * @Flow\Entity
 * @Gedmo\SoftDeleteable(fieldName="deletedAt")
 */
class SomeEntity {

	use SoftDeletableTrait;

	/** ..other properties ..*/

}
?>

Adding @Gedmo\SoftDeleteable(fieldName="deletedAt") annotation to your entity to every entity is quite a hustle 😅

While using 'deletedAt' column name for soft deletion, one can use the SoftDeleteableEntity which doesn't require annotations.