The effects of the Archfey warlock's Fey Presence feature and those of the charm person spell seem very similar; they both can induce the charmed condition on targets who fail their saving throw.
However, the description of Charm Person (PHB, p. 221) states:
When the spell ends, the creature knows it was charmed by you.
But the Archfey warlock's Fey Presence feature (PHB, p. 109) says
As an action, you can cause each creature in a 10-foot cube
originating from you to make a Wisdom saving throw against your
warlock spell save DC. The creatures that fail their saving throws are
all charmed or frightened by you (your choice) until the end of your
next turn.
The key thing is that there's no mention of the creature knowing it was charmed with Fey Presence.
RAW (and rules-lawyering) would say Fey Presence doesn't come with the side-effect of the creature knowing it was charmed. It doesn't even say you cast a spell, just that the effect does or doesn't happen based on a spell save DC.
Is the Fey Presence feature a non-spell, no-"hey you charmed me!"-hangover version of Charm Person?
Best Answer
Fey Presence does not mention the target knowing about being charmed. There is no general rule whether a target knows what conditions are imposed on them --- presumably they'd know if they were knocked prone, or frightened. Charmed creatures realizing they were charmed after the spell is mentioned in spells like Charm Person and Charm Monster, which would indicate (by the common principle of exceptions proving the rule) that targets of charms are usually unaware of their condition even after the charm ending. However, in the absence of more explicit rules, I recommend discussing this around the table to arrive at a consensus the whole group can agree with.
No; the spell and Fey Presence do different things. Both can charm the target, but importantly, the spell's description states that:
This is not an effect of being charmed by other means (including Fey Presence), and therefore Fey Presence is not a complete substitute of Charm Person. Furthermore, Fey Presence only works for a single turn, while Charm Person lasts an entire hour.