Dual tax avoidance

Hi,

I want to know if somebody joined a company at Germany where there is Dual Tax Avoidance Treety singed. 

And for finicial year, he stayed more than 182 days as per rule he is Resident of India till next year March and then whether he need to pay taxes on his German income.

though he is paying TAXes according to German law at Germany.

What are things can exempted ?

Slab is same for Dual taxation as for Indian TAX slabs ?

Regards,

Mrityunjit