What would be the molar concentration of human DNA in a normal human cell?
I will assume that be "molar concentration of DNA", you mean "molar concentration of nucleotides".

Cell size

Assuming a cell with a radius of 0.05 nm (nanometer). Assuming a perfect sphere, the volume of such sphere is $5.24\cdot 10^{-4} nm^3 = 5.24\cdot 10^{-11} L$.

Of course, cell volume varies a lot among different cell types. The final result will drastically depend upon the cell volume considered (Thanks to @Roland fo highlighting that in the comment).

Number of nucleotides

In the nucleus

The haploid genome size is about $3.2\cdot 10^9$ nucleotides. The whole genome is therefore $6.4\cdot 10^9$ nucleotides. As there are two DNA strands at each haploid genome, we have to further multiply by two to get $1.28\cdot 10^{10}$ nucleotides. Note that this number could be lower at other moment of the life cycle. What I am computing here is the maximal number of nucleotides per nucleus

In the mitochondria

There are about 1500 mitochondria per cell. Each mitochondria contains about 16,000 nucleotides resulting in a total of $2.4\cdot 10^7$ nucleotidesin mitochondria per cell.

mitochondria + nucleus

$2.4\cdot 10^7 + 1.28\cdot 10^{10} ≈ 1.28\cdot 10^{10}$. That is mtDNA is negligible.

In the mols

The Avogadro number is about $6 \cdot 10 ^{23}$. Hence, there are $\frac{1.28\cdot 10^{10}}{6\cdot 10^{23}} = 3.2\cdot 10^{-14}$ mols of nucleotides per cell.

Molarity

Molarity is defined is defined as the number of mols per liter. It is therefore

$$\frac{3.2\cdot 10^{-14}}{5.24\cdot 10^{-11}} ≈ 0.0006M$$