Sebastien Gaillemin and Stephanie Klein denied knowing that a group of teenagers were hiding in an electricity sub-station near their homes in the Clichy-sous-Bois housing project northeast of Paris on October 27, 2005.
Bouna Traore, 15, and Zyed Benna, 17, died after being electrocuted, and a third boy was severely burned.
The court heard transcripts of police radio exchanges from that evening indicating the officers recognised there was a danger.
"They are climbing over to get to the EDF (electric company) site. If they enter the EDF site, I don't give them much of a chance," Gaillemin was heard saying in one recording.
Taking the stand, an emotional Gaillemin said he was only aware the boys were running "towards the site" and was not sure they had actually entered it.
His colleague Klein said: "I did not see an electricity station -- only an administrative site."
"I did not react at all," she said, before bursting into tears.
Gaillemin and Klein are being tried for "non-assistance to individuals in danger", a charge carrying a maximum prison term of five years, and fines of up to €75,000 ($79,000).
Supporters of the victims' families said the boys were well-behaved and had only run away because they feared harassment.
The deaths sparked rioting, arson, and running clashes with security forces in Clichy and quickly spread across hundreds of other communities, lasting for three weeks.
The trial is due to conclude on Friday.