In season 3 of The Originals, when Camille died with vampire blood in her system and woke up, Klaus tried to seduce her to drink human blood to complete the transition. She refused. He didn't want to lose her, so he even forced her to drink human blood. But, he didn't compel her to drink human blood.
So, I wondered whether an original vampire can compel someone in transition. It's a grey area because the same episode said that she was neither dead nor alive (a mystical shield couldn't let anyone dead or alive cross, but she crossed). Based on The Vampire Diaries (which shares the same universe with The Originals), any vampire including originals can compel an alive (human) and original vampires can compel even dead (vampires), but what about someone in transition?
This particular scene in which Klaus didn't compel Camille doesn't give evidence that someone in transition can't be compelled because there can be other reasons why he didn't compel her. I just watched that episode randomly on TV (I had stopped watching The Originals in season 2), so I don't exactly have state Camille was in. But, based on flashback, an another vampire girl who was jealous that Klaus loved Camille instead of her compelled Camille to take her blood and slit her own throat. So if she wanted Klaus to suffer, it's possible that she made sure that Camille couldn't be compelled (there are herbs and witches to screw things up). Or, maybe, Klaus simply didn't want to compel the woman he loved.
Can an original vampire compel someone in transition? Can a normal vampire compel someone in transition?