Form 15g.. please help

One of my client pays interest of Rs 15000 during financial year. But the person to whom he pays the interest is having income less than maximum amount not chargeable to tax. My question is whether am i required to deduct tax, or Form 15G would be sufficient ? Can Form 15G help me out from deducting TDS ? Form 15G is applicable for banks only or in this case also will form 15G work ? Please reply urgently