No, this is not allowed. Under certain conditions, your employer may use cameras to protect personnel and property. But your employer may not use these camera images to call employees to account or assess their performance.
Not permitted for another purpose
This is incompatible with the original purpose of using cameras: the protection of personnel and property. In other words, your employer may not simply use images taken for security purposes for any other purpose.
No hidden camera
This does not only apply to the use of camera images. Your employer is also not permitted to use camera images to assess how you do your work if these images were taken using a hidden camera. In most cases, this is too much of an invasion of your privacy.
Your employer is also not permitted to secretly film you for training purposes. Such as mystery shopping with a hidden camera.
Your employer may only use a hidden camera to detect theft or fraud, for example. And then only as a last resort. For other purposes, such as training purposes, a hidden camera is too severe a tool.