As a native speaker I perceive no difference in meaning. However, I consider "let be" as standard and "leave be" as a regional variant. Besides, the Beatles used "Let it be":

When I find myself in times of trouble
Mother Mary comes to me
Speaking words of wisdom, let it be.
And in my hour of darkness
She is standing right in front of me
Speaking words of wisdom, let it be.
Let it be, let it be.
Let it be, let it be.
Whisper words of wisdom, let it be.

And when the broken hearted people
Living in the world agree,
There will be an answer, let it be.
For though they may be parted there is
Still a chance that they will see
There will be an answer, let it be.

Let it be, let it be.
Let it be, let it be.
Yeah, There will be an answer, let it be.

Let it be, let it be.
Let it be, let it be.
Whisper words of wisdom, let it be.
(instrumental break)

Let it be, let it be.
Let it be, yeah let it be.
Whisper words of wisdom, let it be.

And when the night is cloudy,
There is still a light that shines on me.
Shine until tomorrow, let it be.
I wake up to the sound of music
Mother Mary comes to me
There will be no sorrow

Let it be, let it be.

I think there's a notable difference in tone between let something be and let someone be.

Let someone be is a colloquial, almost substandard phrase. It means leave someone alone. Leave him be is even more casual, and more substandard.

Let it be is more standard, less casual.

(This is my opinion from the AE perspective.)

I agree.

leave so. alone - normal, standard
let so. be - colloquial
leave so. be - colloquial, nonstandard

Upon reflection, I agree with eric and hm-us.

I agreed with both of you already! We're just all so agreeable ... (-:

Just to avoid any misunderstanding... I fully agree. :-)

A perfect trifecta! d-:

Robert;

rather:

a trifolium

And what about a good translation....
How could i say that in german?