"It is two years since Paul and Jane moved to Paris." is still correct, even though less common.
For example, have a look at this quote by Sally Brampton (which is the best example Google spewed out at a quick glance
— I'm sure there are many more to find)
It is two years since I emerged from depression
and I no longer want myself dead.
I want myself alive.
You might also want to have a look at English Grammar in Use : a reference and practice book for intermediate students of English by Raymond Murphy.
ell.stackexchange.com/users/19578/Wottensprels
As Sprottenwels says in their answer (emphasis mine):
"It is two years since Paul and Jane moved to Paris." is still correct, even though less common .
You could make this more common by inserting the word now : It is now two years since Paul and Jane moved to Paris
ell.stackexchange.com/users/11145/AndyT
AndyT's variation on Sprottenwels' answer is probably the most natural sounding, but I'll offer this alternative (which is similar to a comment by Jim)
It is Paris to which Paul and Jane moved two years ago This variant emphasises
Paris (i.e. where they moved to) rather than the two years
(i.e. when they moved), which might be desirable depending on the context.
However, it's a slightly old-fashioned construction.
The only similar quote I could find was from Jean Paul Sartre in his essay
" What is Literature ":
It is Paris to which writers from the provinces, if they are well-off, come to practise regionalism
ell.stackexchange.com/users/59148/Alec Harkness
It is the case that Paul and Jane moved to Paris two years ago.
There are many ways in which English speakers, and even writers, extend sentences without materially altering the meaning.
Any assertion may be prefaced with one of these:
It is true that ... Believe me when I say ... Actually ...
The fact is ...
I can tell you ...
It is the case that ... In using the latter, the speaker probably feels that the added phrase lends a note of authority or formality.
It is often used when alternatives to the assertion have been suggested or implied.
ell.stackexchange.com/users/59150/Jive Dadson
Just to demonstrate that there are several ways to solve this problem, here's another one in idiomatic English.
It is the third year that Paul and Jane have spent living in Paris.
You can't change the verb, but you still have a ton of flexibility since the subject of the sentence hasn't been nailed down for you.
ell.stackexchange.com/users/8660/Racheet
Paul and Jane moved to Paris two years ago.      It is...     If the starting words were "it has" I could have written "It has been two years since...". But the auxiliary "be" is used instead and I am not allowed to change it. I don't have a single idea what the solution might be.
I need to rewrite this sentence while keeping the same meaning and starting with the given word(s)
ell.stackexchange.com
<meaning><grammar>
ell.stackexchange.com/questions/135995
ell.stackexchange.com/users/None/
It is  now  two years since Paul and Jane moved to Paris. It is  now  two years since Paul and Jane moved to Paris  
You could make this more common by inserting the word  now :   It is  now  two years since Paul and Jane moved to Paris  